[PATCH] log: fix typo in comment about _matchfiles()

[Yuya Nishihara]

# HG changeset patch
# User Yuya Nishihara <yuya at tcha.org>
# Date 1516106777 -32400
#      Tue Jan 16 21:46:17 2018 +0900
# Node ID 604c08ad12c4c3a2fdf182cdf90d5d4acaa25c9e
# Parent  a62b08f6626bd0f838b2c77a2f1a48068852be1f
log: fix typo in comment about _matchfiles()

diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -2436,7 +2436,7 @@ def _makelogrevset(repo, match, pats, sl
         #
         # pats/include/exclude cannot be represented as separate
         # revset expressions as their filtering logic applies at file
-        # level. For instance "-I a -X a" matches a revision touching
+        # level. For instance "-I a -X b" matches a revision touching
         # "a" and "b" while "file(a) and not file(b)" does
         # not. Besides, filesets are evaluated against the working
         # directory.