docs: Update CPython differences and improve the look of table layouts.

Updated some of the CPython feature differences:
- Updated status of some features.
- Added CSS to fix table widths to 100% and word wrap.
- Specified explicit table column ratios to improve layout appearance.
- Added missing references to anchors.
- Better consistency with use of formatting and case.

1 files changed, 70 insertions, 57 deletions

diff --git a/docs/differences/python_37.rst b/docs/differences/python_37.rst
index c46678e93..86d1b6e81 100644
--- a/docs/differences/python_37.rst
+++ b/docs/differences/python_37.rst
@@ -5,72 +5,81 @@ Python 3.7
 
 New Features:
 
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | **Features:**                                                                                             | **Status**     |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 538 <https://www.python.org/dev/peps/pep-0538/>`_ | Coercing the legacy C locale to a UTF-8 based    |                |
-  |                                                        | locale                                           |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 539 <https://www.python.org/dev/peps/pep-0539/>`_ | A New C-API for Thread-Local Storage in CPython  |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 540 <https://www.python.org/dev/peps/pep-0540/>`_ | UTF-8 mode                                       |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 552 <https://www.python.org/dev/peps/pep-0552/>`_ | Deterministic pyc                                |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 553 <https://www.python.org/dev/peps/pep-0553/>`_ | Built-in breakpoint()                            |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 557 <https://www.python.org/dev/peps/pep-0557/>`_ | Data Classes                                     |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 560 <https://www.python.org/dev/peps/pep-0560/>`_ | Core support for typing module and generic types |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 562 <https://www.python.org/dev/peps/pep-0562/>`_ | Module __getattr__ and __dir__                   | Partially done |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 563 <https://www.python.org/dev/peps/pep-0563/>`_ | Postponed Evaluation of Annotations              |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 564 <https://www.python.org/dev/peps/pep-0564/>`_ | Time functions with nanosecond resolution        |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 565 <https://www.python.org/dev/peps/pep-0565/>`_ | Show DeprecationWarning in __main__              |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
-  | `PEP 567 <https://www.python.org/dev/peps/pep-0567/>`_ | Context Variables                                |                |
-  +--------------------------------------------------------+--------------------------------------------------+----------------+
+.. table::
+  :widths: 20 60 20
+
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | **Feature**                                                                                               | **Status**                           |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 538 <https://www.python.org/dev/peps/pep-0538/>`_ | Coercing the legacy C locale to a UTF-8 based    |                                      |
+  |                                                        | locale                                           |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 539 <https://www.python.org/dev/peps/pep-0539/>`_ | A New C-API for Thread-Local Storage in CPython  |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 540 <https://www.python.org/dev/peps/pep-0540/>`_ | UTF-8 mode                                       |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 552 <https://www.python.org/dev/peps/pep-0552/>`_ | Deterministic pyc                                |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 553 <https://www.python.org/dev/peps/pep-0553/>`_ | Built-in ``breakpoint()``                        |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 557 <https://www.python.org/dev/peps/pep-0557/>`_ | Data Classes                                     |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 560 <https://www.python.org/dev/peps/pep-0560/>`_ | Core support for typing module and generic types |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 562 <https://www.python.org/dev/peps/pep-0562/>`_ | Module ``__getattr__`` and ``__dir__``           | Partial                              |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 563 <https://www.python.org/dev/peps/pep-0563/>`_ | Postponed Evaluation of Annotations              |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 564 <https://www.python.org/dev/peps/pep-0564/>`_ | Time functions with nanosecond resolution        | Partial [#ftimenanosec]_             |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 565 <https://www.python.org/dev/peps/pep-0565/>`_ | Show DeprecationWarning in ``__main__``          |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
+  | `PEP 567 <https://www.python.org/dev/peps/pep-0567/>`_ | Context Variables                                |                                      |
+  +--------------------------------------------------------+--------------------------------------------------+--------------------------------------+
 
 Other Language Changes:
 
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | async and await are now reserved keywords                                                                | Completed      |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | dict objects must preserve insertion-order                                                               |                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | More than 255 arguments can now be passed to a function; a function can now have more than 255 parameters|                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | bytes.fromhex() and bytearray.fromhex() now ignore all ASCII whitespace, not only spaces                 |                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | str, bytes, and bytearray gained support for the new isascii() method, which can be used to test if a    |                |
-  | string or bytes contain only the ASCII characters                                                        |                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | ImportError now displays module name and module __file__ path whenfrom ... import ... fails              |                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | Circular imports involving absolute imports with binding a submodule to a name are now supported         |                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | object.__format__(x, '') is now equivalent to str(x) rather than format(str(self), '')                   |                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | In order to better support dynamic creation of stack traces, types.TracebackType can now be instantiated |                |
-  | from Python code, and the tb_next attribute on tracebacks is now writable                                |                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | When using the -m switch, sys.path[0] is now eagerly expanded to the full starting directory path, rather|                |
-  | than being left as the empty directory (which allows imports from the current working directory at the   |                |
-  | time when an import occurs)                                                                              |                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
-  | The new -X importtime option or the PYTHONPROFILEIMPORTTIME environment variable can be used to show the |                |
-  | timing of each module import                                                                             |                |
-  +----------------------------------------------------------------------------------------------------------+----------------+
+.. table::
+  :widths: 90 10
+
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | ``async`` and ``await`` are now reserved keywords                                                               | Complete       |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | ``dict`` objects must preserve insertion-order                                                                  |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | More than 255 arguments can now be passed to a function; a function can now have more than 255 parameters       |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | ``bytes.fromhex()`` and ``bytearray.fromhex()`` now ignore all ASCII whitespace, not only spaces                |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | ``str``, ``bytes``, and ``bytearray`` gained support for the new ``isascii()`` method, which can be used to     |                |
+  | test if a string or bytes contain only the ASCII characters                                                     |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | ``ImportError`` now displays module name and module ``__file__`` path when ``from ... import ...`` fails        |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | Circular imports involving absolute imports with binding a submodule to a name are now supported                |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | ``object.__format__(x, '')`` is now equivalent to ``str(x)`` rather than ``format(str(self), '')``              |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | In order to better support dynamic creation of stack traces, ``types.TracebackType`` can now be                 |                |
+  | instantiated from Python code, and the ``tb_next`` attribute on tracebacks is now writable                      |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | When using the ``-m`` switch, ``sys.path[0]`` is now eagerly expanded to the full starting directory path,      |                |
+  | rather than being left as the empty directory (which allows imports from the current working directory          |                |
+  | at the time when an import occurs)                                                                              |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
+  | The new ``-X importtime`` option or the ``PYTHONPROFILEIMPORTTIME`` environment variable can be used to         |                |
+  | show the timing of each module import                                                                           |                |
+  +-----------------------------------------------------------------------------------------------------------------+----------------+
 
 Changes to built-in modules:
 
+.. table::
+  :widths: 90 10
+
   +------------------------------------------------------------------------------------------------------------+----------------+
   | `asyncio <https://docs.python.org/3/whatsnew/3.7.html#asyncio>`_                                           |                |
   +------------------------------------------------------------------------------------------------------------+----------------+
-  | asyncio (many, may need a separate ticket)                                                                 |                |
+  | Too many to list                                                                                           |                |
   +------------------------------------------------------------------------------------------------------------+----------------+
   | `gc <https://docs.python.org/3/whatsnew/3.7.html#gc>`_                                                     |                |
   +------------------------------------------------------------------------------------------------------------+----------------+
@@ -93,3 +102,7 @@ Changes to built-in modules:
   +------------------------------------------------------------------------------------------------------------+----------------+
   | Mostly updates to support nanosecond resolution in PEP564, see above                                       |                |
   +------------------------------------------------------------------------------------------------------------+----------------+
+
+.. rubric:: Notes
+
+.. [#ftimenanosec] Only :func:`time.time_ns` is implemented.