Feature or enhancement

Make _EnumDict, _EnumDict._member_names, and possibly other private names public.

This is to make subclassing EnumType and other advanced behavior supported, such as having multiple values per member.

Linked PRs

• gh-112328: [Enum] Make some private attributes public. #112514
• gh-112328: Document EnumDict in docs and release notes #121720
• gh-112328: Make EnumDict usable on its own and document it #123669
• [3.13] gh-112328: Make EnumDict usable on its own and document it (GH-123669) #128142