update template so that it formats correctly (#5493)

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

@@ -13,10 +13,10 @@ void main() {
     new MaterialApp(
       title: 'Flutter Demo',
       theme: new ThemeData(
-        primarySwatch: Colors.blue
+        primarySwatch: Colors.blue,
       ),
-      home: new FlutterDemo()
-    )
+      home: new FlutterDemo(),
+    ),
   );
 }
 
@@ -40,16 +40,16 @@ class _FlutterDemoState extends State<FlutterDemo> {
   Widget build(BuildContext context) {
     return new Scaffold(
       appBar: new AppBar(
-        title: new Text('Flutter Demo')
+        title: new Text('Flutter Demo'),
       ),
       body: new Center(
-        child: new Text('Button tapped $_counter time${ _counter == 1 ? '' : 's' }.')
+        child: new Text('Button tapped $_counter time${ _counter == 1 ? '' : 's' }.'),
       ),
       floatingActionButton: new FloatingActionButton(
         onPressed: _incrementCounter,
         tooltip: 'Increment',
-        child: new Icon(Icons.add)
-      )
+        child: new Icon(Icons.add),
+      ),
     );
   }
 }