i18n: remove obsolete comments for translators in diffstat generation

Since we do not translate diffstat any more, remove the obsolete comments.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -1461,20 +1461,12 @@ int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
 	 * but nothing about added/removed lines? Is this a bug in Git?").
 	 */
 	if (insertions || deletions == 0) {
-		/*
-		 * TRANSLATORS: "+" in (+) is a line addition marker;
-		 * do not translate it.
-		 */
 		strbuf_addf(&sb,
 			    (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
 			    insertions);
 	}
 
 	if (deletions || insertions == 0) {
-		/*
-		 * TRANSLATORS: "-" in (-) is a line removal marker;
-		 * do not translate it.
-		 */
 		strbuf_addf(&sb,
 			    (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
 			    deletions);