Split InvalidArrayAccess into PossiblyInvalidArrayAccess?

[TysonAndre]

E.g. InvalidArrayAccess: Cannot access array value on non-array variable $preferences of type array<mixed, mixed>|string|float|int|bool|null could be PossiblyInvalidArrayAccess because at least one type is array.

This makes InvalidArrayAccess less likely to be a false positive.

InvalidReturnType could have something similar (T1 vs T1|T2 could have one message, T1 vs string could have a different message)

• E.g. for InvalidReturnType: The declared return type 'string' for a::method is incorrect, got 'string|false' could be BroaderInferredReturnType?

[muglug]

For InvalidReturnType, I want to keep that simple – if the thing can return more than the suggested thing, it's just a wrong return type.

For the special case where B extends A and we return A with an @return B, I have MoreSpecificReturnType.

[muglug]

InvalidReturnType could have something similar (T1 vs T1|T2 could have one message, T1 vs string could have a different message)

E.g. for InvalidReturnType: The declared return type 'string' for a::method is incorrect, got 'string|false' could be BroaderInferredReturnType?

Actually I like this idea, especially give we already have InvalidFalsableReturnStatement. There should be PossiblyInvalidReturnType and PossiblyInvalidReturnStatement issues