i18n: leave \n out of translated diffstat

GETTEXT_POISON scrapes everything in translated strings, including \n.
t4205.12 however needs this \n in matching the end result. Keep this
\n out of translation to make t4205.12 happy.
Signed-off-by: NNguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

diff.c

@@ -1329,7 +1329,7 @@ int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
 
 	if (!files) {
 		assert(insertions == 0 && deletions == 0);
-		return fputs(_(" 0 files changed\n"), fp);
+		return fprintf(fp, "%s\n", _(" 0 files changed"));
 	}
 
 	strbuf_addf(&sb,