Add rstcheck to ansible-test and correct issues. (#23550)

* Add rstcheck to ansible-test.
* Fix rst code-block languages and syntax errors.
* Fix rst inline literals.
* Update python 2 code block to pass tests on py 3.

docs/docsite/rst/dev_guide/developing_python3.rst

@@ -130,6 +130,7 @@ to yield text but instead do the conversion explicitly ourselves. For example:
             # Handle the exception gracefully -- usually by displaying a good
             # user-centric error message that can be traced back to this piece
             # of code.
+            pass
 
 .. note:: Much of Ansible assumes that all encoded text is UTF-8.  At some
     point, if there is demand for other encodings we may change that, but for
@@ -293,7 +294,8 @@ new exception-catching syntax which uses the ``as`` keyword:
 
 Do **not** use the following syntax as it will fail on every version of Python-3:
 
-.. code-block:: python
+.. This code block won't highlight because python2 isn't recognized. This is necessary to pass tests under python 3.
+.. code-block:: python2
 
     try:
         a = 2/0
@@ -399,7 +401,6 @@ Python-2 and Python-3.  You may still see this used in some modules:
 .. code-block:: python
 
     from ansible.module_utils.pycompat24 import get_exception
-    [...]
 
     try:
         a = 2/0