match: override visitdir() in nevermatcher to return False When we changed basematcher.visitdir() in cf15c3cc304c (match: make base matcher return True for visitdir, 2017-07-14), we forgot to add an override in nevermatcher. This led to tests failing in narrowhg. As Durham pointed out, it's high time to add unit tests for the matcher, so this patch also adds a first unit test. Differential Revision: https://phab.mercurial-scm.org/D151