Fix Worker.postMessage signature

https://developer.mozilla.org/en-US/docs/Web/API/Worker/postMessage

Author: japgolly

src/main/scala/org/scalajs/dom/raw/WebWorkers.scala

@@ -48,14 +48,34 @@ class Worker(stringUrl: String) extends AbstractWorker {
  var onmessage: js.Function1[js.Any, _] = js.native
 
  /**
- * The Worker.postMessage() method sends a message to the worker's inner scope.
- * This accepts a single parameter, which is the data to send to the worker.
- * The data may be any value or JavaScript object handled by the structured
- * clone algorithm, which includes cyclical references.
+ * The postMessage() method of the Worker interface sends a message to the
+ * worker's inner scope. This accepts a single parameter, which is the data to
+ * send to the worker. The data may be any value or JavaScript object handled
+ * by the structured clone algorithm, which includes cyclical references.
+ *
+ * The Worker can send back information to the thread that spawned it using
+ * the DedicatedWorkerGlobalScope.postMessage method.
  *
  * MDN
+ *
+ * @param aMessage The object to deliver to the worker; this will be in the
+ * data field in the event delivered to the
+ * DedicatedWorkerGlobalScope.onmessage handler. This may be
+ * any value or JavaScript object handled by the structured
+ * clone algorithm, which includes cyclical references.
+ *
+ * @param transferList An optional array of Transferable objects to transfer
+ * ownership of. If the ownership of an object is
+ * transferred, it becomes unusable (neutered) in the
+ * context it was sent from and it becomes available only
+ * to the main thread it was sent to.
+ *
+ * Only MessagePort and ArrayBuffer objects can be
+ * transferred. null is not an acceptable value for the
+ * transferList.
  */
- def postMessage(message: js.Any, ports: js.Any = js.native): Unit = js.native
+ def postMessage(aMessage: js.Any,
+ transferList: js.UndefOr[js.Array[Transferable]] = js.native): Unit = js.native
 
  /**
  * The Worker.terminate() method immediately terminates the Worker. This does