i18n: git-add "Unstaged changes" message

Make the "Unstaged changes after refreshing the index:"
translatable. It's displayed under `git add --refresh --verbose`.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/add.c

@@ -188,7 +188,7 @@ static void refresh(int verbose, const char **pathspec)
 		/* nothing */;
 	seen = xcalloc(specs, 1);
 	refresh_index(&the_index, verbose ? REFRESH_IN_PORCELAIN : REFRESH_QUIET,
-		      pathspec, seen, "Unstaged changes after refreshing the index:");
+		      pathspec, seen, _("Unstaged changes after refreshing the index:"));
 	for (i = 0; i < specs; i++) {
 		if (!seen[i])
 			die(_("pathspec '%s' did not match any files"), pathspec[i]);