Misc docsite fixes (#30290)

* Fix refs for local_facts and various cli :option:
* Fix dev_guide/testing_pep8 refs
* remove ref to non-existing 'developing_test_pr'
* Fix ref to ansible-vault encrypt_string
* Removed hard-to-localize colloquialism.
* Rename '_ansible-pull' in playbooks_intro.

It was conflicting with rst/ansible-pull.rst. Nothing
seems to reference it.

* Add explicit targets for and update refs

Replace some ':doc:' use with ':ref:'.

Replace some :ref: to section names with explicit targets
(:doc:`Dynamic vs. Static` -> :ref:`dynamic_vs_static` etc)

* The 'YAML+Jinja' syntax lex fails here, so just use yaml

Since the yaml+jinja highlight fails, code wasnt highlighted
at all, but 'yaml' works more or less.

* just use no lexer for the < python2.6 examples

py3 will fail highlighting them, and 'python2' throws
a lexer warning, and nothing actually highlights it, so
just disable.

docs/docsite/rst/dev_guide/developing_python3.rst

@@ -295,7 +295,7 @@ 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:
 
 .. This code block won't highlight because python2 isn't recognized. This is necessary to pass tests under python 3.
-.. code-block:: python2
+.. code-block:: none
 
     try:
         a = 2/0