match: remove an obsolete comment about util.finddirs()

Obsolete since 8e55c0c642c (util: make util.dirs() and util.finddirs()
include root directory (API), 2017-05-16).

Differential Revision: https://phab.mercurial-scm.org/D6433

mercurial/match.py

@@ -586,7 +586,6 b' class _dirchildren(object):'
         # yields (dirname, basename) tuples, walking back to the root.  This is
         # very similar to util.finddirs, except:
         #  - produces a (dirname, basename) tuple, not just 'dirname'
-        #  - includes root dir
         # Unlike manifest._splittopdir, this does not suffix `dirname` with a
         # slash.
         oldpos = len(path)