name-rev: prefix annotate-stdin with '--' in message

This is an option rather than command.  Make the message convey this
similar to the other messages in the file.

Signed-off-by: Alexander Shopov <ash@kambanaria.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/name-rev.c

@@ -577,7 +577,7 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
 				   N_("ignore refs matching <pattern>")),
 		OPT_GROUP(""),
 		OPT_BOOL(0, "all", &all, N_("list all commits reachable from all refs")),
-		OPT_BOOL(0, "stdin", &transform_stdin, N_("deprecated: use annotate-stdin instead")),
+		OPT_BOOL(0, "stdin", &transform_stdin, N_("deprecated: use --annotate-stdin instead")),
 		OPT_BOOL(0, "annotate-stdin", &annotate_stdin, N_("annotate text from stdin")),
 		OPT_BOOL(0, "undefined", &allow_undefined, N_("allow to print `undefined` names (default)")),
 		OPT_BOOL(0, "always",     &always,