script api can add menu commands

# Conflicts:
#	front/src/Api/IframeListener.ts
#	front/src/iframe_api.ts

front/src/Api/Events/MenuItemRegisterEvent.ts

@@ -0,0 +1,10 @@
+import * as tg from "generic-type-guard";
+
+export const isMenuItemRegisterEvent =
+    new tg.IsInterface().withProperties({
+        menutItem: tg.isString
+    }).get();
+/**
+ * A message sent from the game to the iFrame when a user enters or leaves a zone marked with the "zone" property.
+ */
+export type MenuItemRegisterEvent = tg.GuardedType<typeof isMenuItemRegisterEvent>;