typing: suppress an import-error warning in `mercurial/utils/resourceutil.py`
Newly caught by pytype 2021-09-09.
Differential Revision: https://phab.mercurial-scm.org/D11468
https://bz.mercurial-scm.org/1089
$ hg init
$ mkdir a
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ hg ci -m m a
$ mkdir a b
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ cd b
Relative delete:
$ hg ci -m m ../a
$ cd ..