The documentation is build with sphinx, see sphinx tutorial.
Sourcecode documentation is build from python docstrings in the source itself.
Other documentation, like this document, is written in reST with additional sphinx-syntax, espacially for internal links or cross-references.
The documentation root dir is docs/. The .rst-files contain all custom documentation. The most important elements are:
Headlines
=========
paragraphs
`links <url>`_
You can build your documentation code with:
(env)$ docs/make html
In some cases use:
(env)$ docs/make clean html
Afterwards open file:///<project_path>/docs/_build/html/index.html, test your documentation and commit your changes.