objcdoc fix for some ambiguity (#14367)

shell/platform/darwin/ios/framework/Headers/FlutterEngine.h

@@ -122,7 +122,7 @@ FLUTTER_EXPORT
  * contains `main()`), using `main()` as the entrypoint (the default for Flutter projects).
  *
  * The first call to this method will create a new Isolate. Subsequent calls will return
- * immediately.
+ * immediately and have no effect.
  *
  * @return YES if the call succeeds in creating and running a Flutter Engine instance; NO otherwise.
  */
@@ -133,7 +133,7 @@ FLUTTER_EXPORT
  * contains `main()`).
  *
  * The first call to this method will create a new Isolate. Subsequent calls will return
- * immediately.
+ * immediately and have no effect.
  *
  * @param entrypoint The name of a top-level function from the same Dart
  *   library that contains the app's main() function.  If this is FlutterDefaultDartEntrypoint (or
@@ -149,7 +149,7 @@ FLUTTER_EXPORT
  * which may not be the same as the library containing the Dart program's `main()` function.
  *
  * The first call to this method will create a new Isolate. Subsequent calls will return
- * immediately.
+ * immediately and have no effect.
  *
  * @param entrypoint The name of a top-level function from a Dart library.  If this is
  *   FlutterDefaultDartEntrypoint (or nil); this will default to `main()`.  If it is not the app's

shell/platform/darwin/ios/framework/Headers/FlutterViewController.h

@@ -105,11 +105,15 @@ FLUTTER_EXPORT
 - (NSString*)lookupKeyForAsset:(NSString*)asset fromPackage:(NSString*)package;
 
 /**
- * Sets the first route that the Flutter app shows. The default is "/".
- * This method will guarnatee that the initial route is delivered, even if the
- * Flutter window hasn't been created yet when called. It cannot be used to update
- * the current route being shown in a visible FlutterViewController (see pushRoute
- * and popRoute).
+ * Attempts to set the first route that the Flutter app shows if the Flutter
+ * runtime hasn't yet started. The default is "/".
+ *
+ * This method must be called immediately after `initWithProject` and has no
+ * effect when using `initWithEngine` if the `FlutterEngine` has already been
+ * run.
+ *
+ * Setting this after the Flutter started running has no effect. See `pushRoute`
+ * and `popRoute` to change the route after Flutter started running.
  *
  * @param route The name of the first route to show.
  */