trailer --parse help: expose aliased options

The existing description "set parsing options" is vague, because
arguably _all_ of the options for interpret-trailers have to do with
parsing to some degree.

Explain what this flag does to match what is in the docs, namely how
it is an alias for "--only-trailers --only-input --unfold".

Signed-off-by: Linus Arver <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Linus Arver

builtin/interpret-trailers.c

@@ -107,7 +107,7 @@ int cmd_interpret_trailers(int argc, const char **argv, const char *prefix)
 		OPT_BOOL(0, "only-trailers", &opts.only_trailers, N_("output only the trailers")),
 		OPT_BOOL(0, "only-input", &opts.only_input, N_("do not apply config rules")),
 		OPT_BOOL(0, "unfold", &opts.unfold, N_("join whitespace-continued values")),
-		OPT_CALLBACK_F(0, "parse", &opts, NULL, N_("set parsing options"),
+		OPT_CALLBACK_F(0, "parse", &opts, NULL, N_("alias for --only-trailers --only-input --unfold"),
 			PARSE_OPT_NOARG | PARSE_OPT_NONEG, parse_opt_parse),
 		OPT_BOOL(0, "no-divider", &opts.no_divider, N_("do not treat \"---\" as the end of input")),
 		OPT_CALLBACK(0, "trailer", &trailers, N_("trailer"),