sphinx plugin for reading docstrings

[rbturnbull]

The snakemake parser has something which might read docstrings for rules but we need to look into this more.

[smutch]

Here is 95% of a complete Sphinx extension for documenting Snakemake workflows. I still need to document the extension (how meta!), add some more tests, and set up the CI. Any thoughts, advice, or suggestions are more than welcome!

Here is an example of the type of Sphinx rst file you can write with the extension.