Document --numstat in git-apply and git-diff

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index f12082e..da1cc60 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -19,7 +19,9 @@
 --numstat::
 	Similar to \--stat, but shows number of added and
 	deleted lines in decimal notation and pathname without
-	abbreviation, to make it more machine friendly.
+	abbreviation, to make it more machine friendly.  For
+	binary files, outputs two `-` instead of saying
+	`0 0`.
 
 --shortstat::
 	Output only the last line of the --stat format containing total