Guido, do you have an opinion on adding `RegexFlag` to the `re` module's `__all__` and documenting it?

There is also some discussion on making these types of int-to-Enum conversions use a `module.name` repr instead of `class.name`:

used to be:

    >>> re.I
    <RegexFlag.I: 2>

is now:

    >>> re.I
    re.IGNORECASE

I of course have no idea if that matters to typing one way or the other.