`@commands.check` and `@error` method typings/docs are not entirely accurate

[shiftinv]

This is sort of a rehash of #614 (and #1045).
There are still a couple issues, mainly when used in cogs, many owing to the fact that overloads and generic callables don't really mix well :/

1. @check/@error decorators in cogs trip up pyright already in fairly simple configurations
2. The documented parameter/return types of checks are slightly off in many cases, especially bool vs Coro[bool]
   • Tangentially related, the CheckAnyFailure attribute docs are the wrong way around
3. The usage of AnyContext in some decorator annotations is somewhat inconsistent
4. Callable[[A | B], C] vs Callable[[A], C] | Callable[[B], C]