[PATCH 1 of 4 STABLE] subrepo: update the help text to account for diff -I/-X gitsubrepo support

[Matt Harbison]

# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1430180709 14400
#      Mon Apr 27 20:25:09 2015 -0400
# Branch stable
# Node ID a6e1457cd2ec16cb77b2e05d32b92e4ea1609b48
# Parent  bff42a92012e49aabd925caa3cb243116285e243
subrepo: update the help text to account for diff -I/-X gitsubrepo support

The functionality was added in a48b65ab428d.

diff --git a/mercurial/help/subrepos.txt b/mercurial/help/subrepos.txt
--- a/mercurial/help/subrepos.txt
+++ b/mercurial/help/subrepos.txt
@@ -106,8 +106,7 @@
 
 :diff: diff does not recurse in subrepos unless -S/--subrepos is
     specified. Changes are displayed as usual, on the subrepositories
-    elements. Git subrepositories do not support --include/--exclude.
-    Subversion subrepositories are currently silently ignored.
+    elements. Subversion subrepositories are currently silently ignored.
 
 :files: files does not recurse into subrepos unless -S/--subrepos is
     specified.  Git and Subversion subrepositories are currently