[PATCH] diff: document the nobinary option

[Jordi Gutiérrez Hermoso]

# HG changeset patch
# User Jordi Gutiérrez Hermoso <jordigh at octave.org>
# Date 1412110747 14400
#      Tue Sep 30 16:59:07 2014 -0400
# Node ID accdba3c4b4afbb15252ff7d779de4333b73996b
# Parent  939ce500c92a3dcc0e10815242361ff70a6fcae9
diff: document the nobinary option

Since 3fbef7ac26f0, we have a diff.nobinary option. This is handy, but
the only way I found out about it was by looking at the release notes
for 3.1, which is not something I normally do.

diff --git a/mercurial/help/config.txt b/mercurial/help/config.txt
--- a/mercurial/help/config.txt
+++ b/mercurial/help/config.txt
@@ -519,6 +519,9 @@ related options for the annotate command
 ``git``
     Use git extended diff format.
 
+``nobinary``
+    Omit git binary patches.
+
 ``nodates``
     Don't include dates in diff headers.