feat: make all rules error instead of warn

[G-Rath]

Originally when I authored our configs I set a handful of rules to warn instead of error as a way of making the configs gentler and hint to people when it might be ok to actually disable the rule for that particular violation depending on the context.

In practice however, most people tend to expect the linter to block in CI and that if it doesn't then everything is fine, meaning the rules configured to warn were effectively the same as not being enabled at all except for when people run --fix.

When we've talked about this recently, the general consensus was people would prefer the rules just error, and so that's what this does

[robotdana]

i agree, if it doesn't fail ci it doesn't exist