🐍 Remove .py from linkify domains

[fwkoch]

There are a ton of domains that linkify catches, including py... That means someone writing about their python my_script.py file gets linkified.

For now, I've addressed this by hard-coding excluded domains in myst parser. We may want to make this configurable at the MyST config level...?

I think hardcoding what is excluded is ok, since users can always explicitly make things a link. If something they want linkified is not working (because of our exclude list), they can just make it an explicit link. Potentially we even lock down the domain list way more... there are currently 1450 valid domains 😳 https://github.com/stephenmathieson/node-tlds/blob/master/index.json (1449 with py excluded).

[rowanc1]

This looks great, maybe we can change this to be configured externally rather than bundling the domain list in the parser, but that can come in the future! We should also exclude .md

[rowanc1]

We can also add md here!