nox: add docstring about nox and list command how to use it

[consideRatio]

I think its a great practice to ensure that various things in a github repo is somewhat self-explanatory as that helps anyone trying to onboard do it more efficiently. I didn't know how to use nox myself before doing this, and at one point I didn't know for what reason this file was around or how it was related to a repo I found it in.

A docstring like this can resolve such issues for us!

• Closes Add description about what noxfile.py is #1000

[choldgraf]

This is a great idea. I'm kicking myself for not adding in a little docstring. I think the content looks great and I'd be fine with merging as-is, though I also wonder what @consideRatio thinks about simply linking to our nox documentation in the team compass:

https://compass.2i2c.org/reference/documentation/environment/#install-nox

(or potentially making that a dedicated section on Nox so that it's more discoverable). That way, we can point all of our noxfile.py files to that site, and update the site's content without needing to update each individual file.

[consideRatio]

Thanks for reviewing and approving it as it is @choldgraf!!! ❤️ 🎉

For this brief intro that I think by itselfs does a good enough job, I think its a good call to break the DRY principle and directly write it all noxfile.py files.

If we were to link to a centralized intro, I still think it would make sense to provide a brief intro like this before linking out as otherwise it may not be enticing enough to click the link in the first place.

[consideRatio]

Ah missed that there was existing docs to link to already.

I think adding a link to that could make sense to learn a bit more, but that the first paragraph and config ref link is worth retaining inlined in the file.