Small update to instructional comments in app template (#8468)

* Small update to instructional comments in app template

* Update Flutter Driver comment

Good suggestion to add the link, Seth! I also updated the working to match what that page uses.

packages/flutter_tools/templates/create/lib/main.dart.tmpl

@@ -5,8 +5,8 @@ import 'package:flutter_driver/driver_extension.dart';
 
 void main() {
 {{#withDriverTest}}
-  // Starts the app with Flutter Driver extension enabled to allow Flutter Driver
-  // to test the app.
+  // Enable integration testing with the Flutter Driver extension.
+  // See https://flutter.io/testing/ for more info.
   enableFlutterDriverExtension();
 {{/withDriverTest}}
   runApp(new MyApp());
@@ -24,9 +24,10 @@ class MyApp extends StatelessWidget {
         // Try running your application with "flutter run". You'll see
         // the application has a blue toolbar. Then, without quitting
         // the app, try changing the primarySwatch below to Colors.green
-        // and press "r" in the console where you ran "flutter run".
-        // We call this a "hot reload". Notice that the counter didn't
-        // reset back to zero -- the application is not restarted.
+        // and then invoke "hot reload" (press "r" in the console where
+        // you ran "flutter run", or press Run > Hot Reload App in IntelliJ).
+        // Notice that the counter didn't reset back to zero -- the application
+        // is not restarted.
         primarySwatch: Colors.blue,
       ),
       home: new MyHomePage(title: 'Flutter Demo Home Page'),
@@ -91,8 +92,7 @@ class _MyHomePageState extends State<MyHomePage> {
         onPressed: _incrementCounter,
         tooltip: 'Increment',
         child: new Icon(Icons.add),
-      ), // This trailing comma tells the Dart formatter to use
-      // a style that looks nicer for build methods.
+      ), // This trailing comma makes auto-formatting nicer for build methods.
     );
   }
 }