commit,merge,tag: describe -m likewise

This also removes the superfluous "specify" and rewords the misleading
"if any" which sounds as if omitting "-m" would omit the merge commit
message. (It means "if a merge commit is created at all".)

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/commit.c

@@ -121,7 +121,7 @@ static struct option builtin_commit_options[] = {
 	OPT_FILENAME('F', "file", &logfile, "read message from file"),
 	OPT_STRING(0, "author", &force_author, "AUTHOR", "override author for commit"),
 	OPT_STRING(0, "date", &force_date, "DATE", "override date for commit"),
-	OPT_CALLBACK('m', "message", &message, "MESSAGE", "specify commit message", opt_parse_m),
+	OPT_CALLBACK('m', "message", &message, "MESSAGE", "commit message", opt_parse_m),
 	OPT_STRING('c', "reedit-message", &edit_message, "COMMIT", "reuse and edit message from specified commit"),
 	OPT_STRING('C', "reuse-message", &use_message, "COMMIT", "reuse message from specified commit"),
 	OPT_STRING(0, "fixup", &fixup_message, "COMMIT", "use autosquash formatted message to fixup specified commit"),

builtin/merge.c

@@ -194,8 +194,8 @@ static struct option builtin_merge_options[] = {
 		"merge strategy to use", option_parse_strategy),
 	OPT_CALLBACK('X', "strategy-option", &xopts, "option=value",
 		"option for selected merge strategy", option_parse_x),
-	OPT_CALLBACK('m', "message", &merge_msg, "message",
-		"message to be used for the merge commit (if any)",
+	OPT_CALLBACK('m', "message", &merge_msg, "MESSAGE",
+		"merge commit message (for a non-fast-forward merge)",
 		option_parse_message),
 	OPT__VERBOSITY(&verbosity),
 	OPT_BOOLEAN(0, "abort", &abort_current_merge,

builtin/tag.c

@@ -376,8 +376,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		OPT_GROUP("Tag creation options"),
 		OPT_BOOLEAN('a', NULL, &annotate,
 					"annotated tag, needs a message"),
-		OPT_CALLBACK('m', NULL, &msg, "msg",
-			     "message for the tag", parse_msg_arg),
+		OPT_CALLBACK('m', NULL, &msg, "MESSAGE",
+			     "tag message", parse_msg_arg),
 		OPT_FILENAME('F', NULL, &msgfile, "read message from file"),
 		OPT_BOOLEAN('s', NULL, &sign, "annotated and GPG-signed tag"),
 		OPT_STRING('u', NULL, &keyid, "key-id",