tests/failfilemerge.py

typing: add some trivial type hints to `mercurial/match.py`

These were new methods since hg 3dbc7b1ecaba, but surprisingly pytype couldn't
figure them out.

# extension to emulate interrupting filemerge._filemerge


from mercurial import (
    error,
    extensions,
    filemerge,
)


def failfilemerge(*args, **kwargs):
    raise error.Abort(b"^C")


def extsetup(ui):
    extensions.wrapfunction(filemerge, 'filemerge', failfilemerge)