Remove extra '-' from git-am(1)

Signed-off-by: Michal Sojka <sojkam1@fel.cvut.cz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/git-am.txt b/Documentation/git-am.txt
index 67ad5da..40178be 100644
--- a/Documentation/git-am.txt
+++ b/Documentation/git-am.txt
@@ -44,7 +44,7 @@
 	Remove everything in body before a scissors line (see
 	linkgit:git-mailinfo[1]).
 
----no-scissors::
+--no-scissors::
 	Ignore scissors lines (see linkgit:git-mailinfo[1]).
 
 -q::