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