annotate .arcconfig @ 51721:ed28085827ec

typing: explicitly type some `mercurial.util` eol code to avoid @overload

Unlike the previous commit, this makes a material difference in the generated
stub file- the `pycompat.identity()` aliases generated an @overload like this:

    @overload
    def fromnativeeol(a: _T0) -> _T0: ...

... which might fail to detect a bad argument, like str.  This drops the
@overload for the 3 related methods, so there's a single definition for each.

The `typelib.BinaryIO_Proxy` is used for subclassing (the same as was done in
8147abc05794), so that it is a `BinaryIO` type during type checking, but still
inherits `object` at runtime.  That way, we don't need to implement unused
abstract methods.

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "phabricator.uri": "https://phab.mercurial-scm.org/",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}