Bug #257, continuation of #213

macOS 13 handles All-day events differently from
previous versions. No longer need a hack to handle
All-day events. Now fixed in "Copy" function too.

Itsycal/AgendaViewController.m

@@ -222,6 +222,11 @@ - (void)copyEventToPasteboard:(id)sender
     NSDate *endDate = cell.eventInfo.event.isAllDay
         ? [self.nsCal dateByAddingUnit:NSCalendarUnitDay value:-1 toDate:cell.eventInfo.event.endDate options:0]
         : cell.eventInfo.event.endDate;
+    if (@available(macOS 13.0, *)) {
+        // macOS 13 changed All-day events' end date from 12 AM of
+        // day after last day of event to 11:59:59 PM of last day.
+        endDate = cell.eventInfo.event.endDate;
+    }
     // Interval formatter just prints single date when from == to.
     NSString *duration = [intervalFormatter stringFromDate:cell.eventInfo.event.startDate toDate:endDate];
     // If the locale is English and we are in 12 hour time,