Correctly handle Enum name on Python 3.11

[ilevkivskyi]

Fixes #12483
Fixes python/typeshed#7564
Ref #12841

The fix is straightforward. I can't use a unit test for this because there are some builtins fixtures that don't have tuple, so I can't do version check.

[AlexWaygood]

Looks good, and it's great to have this fixed. This PR also fixes python/typeshed#7564.

There's still the outstanding issue that mypy won't spot that this will raise an AttributeError at runtime on 3.11+:

import enum

class E(enum.Enum):
    X = 1
    @enum.property
    def foo(self) -> int: return 42

assert E.X.foo == 42  # this is fine
E.foo  # AttributeError raised here at runtime

But this is a much lower-priority problem, and can be filed as a follow-up issue.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉