Documentation: update-index: -z applies also to --index-info

Signed-off-by: Bert Wesarg <bert.wesarg@googlemail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index 74d1d49..26fd8d0 100644
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -144,8 +144,8 @@
         Report what is being added and removed from index.
 
 -z::
-	Only meaningful with `--stdin`; paths are separated with
-	NUL character instead of LF.
+	Only meaningful with `--stdin` or `--index-info`; paths are
+	separated with NUL character instead of LF.
 
 \--::
 	Do not interpret any more arguments as options.