Fix typo in comment.

Tomonari Katsumata

src/backend/access/transam/xlog.c

@@ -10245,7 +10245,7 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive, TimeLineID *stoptli_p)
  * an error handler.
  *
  * NB: This is only for aborting a non-exclusive backup that doesn't write
- * backup_label. A backup started with pg_stop_backup() needs to be finished
+ * backup_label. A backup started with pg_start_backup() needs to be finished
  * with pg_stop_backup().
  */
 void