Better linting in the codebase

[JeanKossaifi]

We recently added Black to enforce linting in the codebase, thanks to @j6k4m8 and @aarmey . In hindsight, it makes a lot of sense in most places but I really dislike the way it forces us to format things in some cases, sometimes going against pep8. The main reason is that it makes code less readable in those cases, going against the very reason behind using a linter.

I suggest either:

• applying Black only on changed files in PRs and choosing to deviate from it or
• switching to another linter such as flake8

[aarmey]

One vote here for switching to a different linter, rather than limiting the code over which it is applied. Enforcing consistent formatting often greatly simplifies diff views; I find this very helpful.

[cohenjer]

@JeanKossaifi Could you spot a few places where the black formatting does not work for you? It could help us choose a new linter, or maybe modify some options of the black linter itself.

I have no particular attachment to a particular linter but I like the way the code is easy to read since the black linter PR.