Doc: Document installed Sphinx extensions, usable syntax, modifications

[Paebbels]

The Sphinx documentation flow was extended by several sphinx and third party extensions. These extensions should be documented along with their modifications. A comprehensive syntax guide should be assembled, to collect all syntax notations at one place instead of dozens of third party documentation websites with partially poor usage descriptions.

Extensions list:

• Standard Sphinx extensions
  • sphinx.ext.autodoc
  • sphinx.ext.extlinks
  • sphinx.ext.intersphinx
  • sphinx.ext.inheritance_diagram
  • sphinx.ext.todo
  • sphinx.ext.graphviz
  • sphinx.ext.mathjax
  • sphinx.ext.ifconfig
  • sphinx.ext.viewcode
• SphinxContrib extensions
  • sphinxcontrib.wavedrom
  • autoapi.sphinx
• local extensions (patched)
  • autoprogram (derived from sphinxcontrib.autoprogram)
• local extensions
  • DocumentMember
  • PoC

Syntax:

• from docutils
• from Sphinx
• from Sphinx extensions
• from own extensions