add json US

resource/locales/en_US/translation.json

@@ -300,7 +300,8 @@
     "label": {
       "Duplicate page": "Duplicate page",
       "New page name": "New page name",
-      "Current page name": "Current page name"
+      "Current page name": "Current page name",
+      "Duplicate with child": "Duplicate with child"
     }
   },
   "modal_putback": {