Add entity definition for autocomplete

app/client/src/utils/autocomplete/EntityDefinitions.ts

@@ -670,6 +670,11 @@ export const GLOBAL_FUNCTIONS = {
     "!doc": "Stop executing a setInterval with id",
     "!type": "fn(id: string) -> void",
   },
+  postMessage: {
+    "!doc":
+      "Establish cross-origin communication between Window objects/page and iframes",
+    "!type": "fn(message: any, targetOrigin: any, transfer: [any])",
+  },
 };
 
 export const getPropsForJSActionEntity = ({