Include enums in unrelated_type_equality_checks

[minhqdao]

Fixes comparisons of enums in unrelated_type_equality_checks.

Currently:

enum One { one }
enum Two { one }

void hello() {
  const one = One.one;
  const two = Two.one;

  if (one == two) {} // Can't be, but no lint
}

Closes dart-lang/sdk#58653.

[coveralls]

Coverage increased (+0.0006%) to 95.63% when pulling 84be139 on minhqdao:include-enums-in-unrelated-type-equality-checks into 90e8ad5 on dart-lang:master.

[srawlins]

Great feature, thanks!

Would you mind resolving the conflict? I can check our internal code for fixed false negatives before landing this.

[minhqdao]

Great feature, thanks!

Would you mind resolving the conflict? I can check our internal code for fixed false negatives before landing this.

It's now been fixed here: #4282.

I think this PR and the respective issue dart-lang/sdk#58653 can be closed.

[srawlins]

Thanks, you're right!