[#46] Windows: Add PaymentAdjustmentWindow

Elwig/App.xaml.cs

@@ -296,6 +296,10 @@ namespace Elwig {
             return FocusWindow<PaymentVariantsWindow>(() => new(year), w => w.Year == year);
         }
 
+        public static PaymentAdjustmentWindow FocusPaymentAdjustment(int year) {
+            return FocusWindow<PaymentAdjustmentWindow>(() => new(year), w => w.Year == year);
+        }
+
         public static ChartWindow FocusChartWindow(int year, int avnr) {
             return FocusWindow<ChartWindow>(() => new(year, avnr), w => w.Year == year && w.AvNr == avnr);
         }