chapel-py: Apply black to chapel-py and its derivative files.

[DanilaFe]

We've done this before on files such as chpl-language-server.py or chplcheck.py or rules.py. This PR just does that again, but also applies it to other, less-often formatted files.

Reviewed by @jabraham17 -- thanks!

Testing

• validated using the new CI check

[jabraham17]

I realized after reviewing that black defaults to line widths of 88. Did you run it with that default line width, or some other width?

[DanilaFe]

I did it with line with 80, which we have been using ourselves.