Describe various forms of "be quiet" using OPT__QUIET

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/commit.c b/builtin/commit.c
index 97ae1bc..4fd1a16 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -114,8 +114,8 @@
 }
 
 static struct option builtin_commit_options[] = {
-	OPT__QUIET(&quiet, "be quiet"),
-	OPT__VERBOSE(&verbose, "be verbose"),
+	OPT__QUIET(&quiet, "suppress summary after successful commit"),
+	OPT__VERBOSE(&verbose, "show diff in commit message template"),
 
 	OPT_GROUP("Commit message options"),
 	OPT_FILENAME('F', "file", &logfile, "read log from file"),