Update linting

[sco1]

Per #384, this PR updates the django branch's linting dependencies & relints the codebase.

To potentially help ease review I've split the diffs into discrete chunks, but can squash them into a single commit if preferable.

Closes: #384

[SebastiaanZ]

Partial review, my time's up for now, but I think leaving a partial review speeds up the process with such a large number of changes. I've gone through the files manually and checked the function signatures myself.

Also, why doesn't this cause a linting error? It seems to be missing a return type annotation:
Edit: We've ignored TYP206/classmethod return value annotations.

bot/bot/pagination.py

Lines 303 to 306 in 138567f

	@classmethod
	async def paginate(cls, pages: List[Tuple[str, str]], ctx: Context, embed: Embed,
	prefix: str = "", suffix: str = "", timeout: int = 300,
	exception_on_empty_embed: bool = False):

[SebastiaanZ]

I've looked through all the files now, I think.

This inner-function in bot.cogs.utils does not have a return value annotation, it should be Tuple[str, str]

[SebastiaanZ]

Apparently, I messed a few things during my review; apologies.

I'm going to look over the code once again to make sure I haven't missed more of those.

[lemonsaurus]

looks phenomenal

[MarkKoz]

I'm currently reviewing this by the way

[MarkKoz]

This is great, thanks!