Simplify recur_apoint_switch_notify()

Pass the recurrent appointment itself instead of passing a date and an
item number. This is quite simple as we can just pass the pointer that
is contained in the generic item structure and don't have to
LLIST_TS_FIND_*() the item first any more.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

src/apoint.c

@@ -560,7 +560,7 @@ void apoint_switch_notify(void)
   date = calendar_get_slctd_day_sec();
 
   if (p->type == RECUR_APPT) {
-    recur_apoint_switch_notify(date, p->appt_pos);
+    recur_apoint_switch_notify(p->item.rapt);
     return;
   } else if (p->type == APPT)
     apoint_nb = day_item_nb(date, hilt, APPT);