Convert docs from rst to md?

[pauleveritt]

I wanted the docs top page to share the content from the README. But it's README.md not README.rst.

I propose switching to MyST and Markdown for the stuff in docs. Obviously the PEP would remain in RST, but MyST supports RST/MD mixing.

[merwok]

The readme is short, github supports rendering reST, what about converting to README.rst?

[pauleveritt]

As mentioned in #40 we are stripping down this repo. The tutorial is being worked on as part of a "site" that is on a different timing than the PEP, so closing this.