import-checker: allow 'from typing import ...'
Suppresses the following error in test-check-module-imports.t:
mercurial/encoding.py:24: relative import of stdlib module
Martin von Zweigbergk <martinvonz@google.com> [Tue, 29 Oct 2019 23:33:34 -0700] rev 43640
match: drop support for passing '.' for root dir to visit*() methods
We said we'd drop support for it after 5.1, so it's time to clean it
up now.
Differential Revision: https://phab.mercurial-scm.org/D7249