Here are discussions of what to put in a docstring:
- PEP 257 -- Docstring Conventions - Python.org
- What is the standard Python docstring format? - Stack Overflow
- Javadoc - Wikipedia - A documentation generator for Java code. The conventions Javadoc understands can be adapted for other languages. I'm evaluating tools for processing Python docstrings that use this format.
My snippets for functions and modules will include docstring outlines.
Then you need a tool to present the docstrings to the reader. For now I'm going with Sphinx, since Python developers seem to prefer it. Since it formats more than just docstrings, I've put its links in the "Project documentation" section below.