Add style related info to CONTRIBUTING.rst

[merveenoyan]

I realized we need to almost always remind external contributors to run black on their code. It would be nice to add black (or extra note about pre-commit hooks) to contribution guidelines. I had to help an external contributor from DM because they didn't know what type of change does running black made on their code. (I guess people don't use the snippet to prepare the environment in CONTRIBUTING.rst or don't know what pre-commit hooks are for.

[adrinjalali]

we do have a note in contributing guidelines about pre-commit hooks. But we can make it more clear, and add it to the PR template as well maybe.

[BenjaminBossan]

+1 on being more explicit about black.

It seems, however, that people are not really following the CONTRIBUTING.rst :( We even have a link to it in the README.rst and the docs.

[adrinjalali]

pretty much nobody reads them ;)

[merveenoyan]

@adrinjalali I know that it exists in the contributing.rst, but it looks pretty cryptic in someone's eyes who doesn't know about pre-commit hooks (and that's what I mean on adding an extra note) @BenjaminBossan I'm currently adding PR template which might encourage people to read it.

[adrinjalali]

are we happy now? Anything we need to do for this issue?

[merveenoyan]

@adrinjalali it already exists in PR template, I say if we come across folks that still commit code that don't fit to style guide we can add to contributing.rst.