Lint group for performance/ignoring style

[TheIronBorn]

Is there a lint group to only warn/deny lints which affect performance and ignore all others?

[TheIronBorn]

A group for what look like mistakes might be useful as well. I suppose what I'm looking for is a way to ignore all lints which are merely format differences. Though how that's defined is a difficult question: 0b111_1111 != 0b0b1111_1111 is merely "a formatting difference" and yet might be a typo.

[TheIronBorn]

I just noticed #743 so I'll just toss a mention in here and close.