fix errors

assets/local/localization_mu.json

@@ -457,6 +457,8 @@
     "invoice.shipment_weight":"Shipment weight",
     "invoice.popupmenu.pending":"Pending",
     "invoice.popupmenu.paid":"Paid",
+    "invoice.shipment.title":"Select FCS shipment",
+    "invoice.customer.title":"Select Customer",
     "Invoices End ================================================================":"",
 
     "Discount Start ================================================================":"",
@@ -469,6 +471,8 @@
     "discount.amount":"ပမာဏ",
     "discount.status":"အခြေအနေ",
     "discount.edit.delete.confirm":"လျှော့စျေးကို ဖျက်မလား?",
+    "discount.popupmenu.available":"Available discounts",
+    "discount.popupmenu.used":"Used discounts",
     "Discount End ================================================================":"",
 
     "delivery_addresses Start ================================================================":"",