org-agenda: Fix scheduled repeats

* lisp/org-agenda.el (org-agenda-get-scheduled): Fix scheduled
  repeats.

This is a follow-up to b5c19643d2347e4e1f4d76634b458380a46e39c4.

lisp/org-agenda.el

@@ -6214,7 +6214,7 @@ scheduled items with an hour specification like [h]h:mm."
 		     (pcase-let ((`(,first ,past) org-agenda-scheduled-leaders))
 		       ;; Show a reminder of a past scheduled today.
 		       (if (and todayp pastschedp)
-			   (format past (1+ diff))
+			   (format past diff)
 			 first))
 		     head level category tags time nil habitp))
 		   (face (cond ((and (not habitp) pastschedp)