Comply with Black " vs '

[LukeDRussell]

In PR561 klardotsh indicated he'd be OK with moving KMK to be fully compliant with Black's opinionated use of double quotes (" vs. ').

The benefit of this change is:

• contributors can run black (deliberately or as part of tests and CI) to have all quotes fixed and standardised. Right now double quotes (") need to be changed manually to single quotes.
• Less divergence from a Python "standard" style. Yes black is highly opinionated.

This Issue is to track that work.

Introducing Black will be the primary reference. Particularly the guidance to have everything change in one commit, and introcucing a ignore-rev file to make git blame a little more usefull.

I will do the work to provide a single commit that refactors all of KMK. Though of course I will need QA from the maintainers.

[klardotsh]

For what it's worth, while I support the move to get rid of a weird vestigial exception case I put in for subjective reasons (back while the debate was still warm over that issue in the community), there should not be a "manually change" step unless something changed on Black's side. I distinctly remember Black's auto-fixer handling this due to the stuff in setup.cfg at one point...

[kdb424]

At this point, I don't really care. I just want it to be a standard. Pick one, I'll just approve the PR assuming there's no actual code issues.

TLDR: I have no opinion

[LukeDRussell]

...there should not be a "manually change" step unless something changed on Black's side. I distinctly remember Black's auto-fixer handling this due to the stuff in setup.cfg at one point...

I don't understand this point. I've started work in draft PR571 though.