Evaluate MyST (reST-like Markdown flavor) for docs

[astrojuanlu]

https://twitter.com/choldgraf/status/1272633413132943360

https://myst-parser.readthedocs.io/en/latest/index.html

I've been observing the development of MyST over the past few months and I think it's very promising. A real alternative to ditch reST (a markdown language used only in the Python community) while keep most of its interesting features and fixing some of most obvious reST shortcomings.

I posed a question to Chris about docstrings and the NumPy standard, but in any case I think this is worth trying.

[astrojuanlu]

Relevant issues:

• Add an eval_rst directive executablebooks/MyST-Parser#164 closed
• Support use of autodoc with myst executablebooks/MyST-Parser#163 closed

[jorgepiloto]

People from executablebooks also offer converter from *.rst file into *.md ones in their project rst2myst. Might be interesting!

[astrojuanlu]

Worth checking too executablebooks/MyST-Parser#156

[astrojuanlu]

Closed in #1073 🎉