i18n: merge: change command option help to lowercase

Change command option description to lowercase, matching pull
counterpart option. Translators would have to translate such message
only once.
Signed-off-by: NVasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin/merge.c

@@ -211,7 +211,7 @@ static struct option builtin_merge_options[] = {
 		PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
 	OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
 	OPT_BOOL(0, "verify-signatures", &verify_signatures,
-		N_("Verify that the named commit has a valid GPG signature")),
+		N_("verify that the named commit has a valid GPG signature")),
 	OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
 		N_("merge strategy to use"), option_parse_strategy),
 	OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),