Fix issues that broke editing on browsers without Shadow DOM support.

dart/site/try/src/editor.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library trydart.editor;
 
 import 'dart:html';
 
 import 'package:compiler/implementation/scanner/scannerlib.dart' show
     EOF_TOKEN,
@@ skipping 256 matching lines @@
   }
   return currentTheme.foreground;
 }
 
 diagnostic(text, tip) {
   if (text is String) {
     text = new Text(text);
   }
   return new AnchorElement()
       ..classes.add('diagnostic')
-      ..append(text)
-      ..append(tip);
+      ..append(tip)
+      ..append(text);
 }