Make the override warnings prettier.

sdk/lib/_internal/pub/lib/src/source.dart

 // Copyright (c) 2012, 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 pub.source;
 
 import 'dart:async';
 
 import 'package:path/path.dart' as path;
 
@@ skipping 210 matching lines @@
   /// [FormatException] if not valid.
   ///
   /// [fromLockFile] is true when the description comes from a [LockFile], to
   /// allow the source to use lockfile-specific descriptions via [resolveId].
   dynamic parseDescription(String containingPath, description,
                            {bool fromLockFile: false}) {
     return description;
   }
 
   /// When a [LockFile] is serialized, it uses this method to get the
-  /// [description] in the right format. [containingPath] references the
-  /// containing directory of the root package.
+  /// [description] in the right format.
+  ///
+  /// [containingPath] is the containing directory of the root package.
   dynamic serializeDescription(String containingPath, description) {
     return description;
   }
 
+  /// When a package [description] is shown to the user, this is called to
+  /// convert it into a human-friendly form.
+  ///
+  /// By default, it just converts the description to a string, but sources
+  /// may customize this. [containingPath] is the containing directory of the
+  /// root package.
+  String formatDescription(String containingPath, description) {
+    return description.toString();
+  }
+
   /// Returns whether or not [description1] describes the same package as
   /// [description2] for this source. This method should be light-weight. It
   /// doesn't need to validate that either package exists.
   ///
   /// By default, just uses regular equality.
   bool descriptionsEqual(description1, description2) =>
     description1 == description2;
 
   /// For some sources, [PackageId]s can point to different chunks of code at
   /// different times. This takes such an [id] and returns a future that
@@ skipping 18 matching lines @@
   /// Returns the [Package]s that have been downloaded to the system cache.
   List<Package> getCachedPackages() {
     if (shouldCache) {
       throw new UnimplementedError("Source $name must implement this.");
     }
   }
 
   /// Returns the source's name.
   String toString() => name;
 }