pkg/docgen: fixed type references within typedef doc comments

pkg/docgen/lib/src/models/indexable.dart

 // Copyright (c) 2014, 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 docgen.models.indexable;
 
 import 'package:markdown/markdown.dart' as markdown;
 
 import '../exports/mirrors_util.dart' as dart2js_util;
 import '../exports/source_mirrors.dart';
@@ skipping 105 matching lines @@
   ///
   /// "Owning" is defined as the object one scope-level above which this item
   /// is defined. Ex: The owner for a top level class, would be its enclosing
   /// library. The owner of a local variable in a method would be the enclosing
   /// method.
   Indexable get owner => new DummyMirror(mirror.owner);
 
   /// Generates MDN comments from database.json.
   String getMdnComment();
 
-  /// The type of this member to be used in index.txt.
-  String get typeName => '';
+  String get typeName;

[kevmoo, 2014/04/20 21:34:54]

Every type implements this, so making it abstract.

 
   /// Creates a [Map] with this [Indexable]'s name and a preview comment.
   Map get previewMap {
     var finalMap = { 'name' : name, 'qualifiedName' : qualifiedName };
     var pre = preview;
     if (pre != null) finalMap['preview'] = pre;
     return finalMap;
   }
 
   String get preview {
@@ skipping 46 matching lines @@
   /// Return a map representation of this type.
   Map toMap();
 
   /// Accessor to determine if this item and all of its owners are visible.
   bool get isVisible => isFullChainVisible(this);
 
   /// Returns true if [mirror] is the correct type of mirror that this Docgen
   /// object wraps. (Workaround for the fact that Types are not first class.)
   bool isValidMirror(DeclarationMirror mirror);
 }