Fix some bad documentation links.

sdk/lib/io/directory.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.
 
 part of dart.io;
 
 /**
  * A reference to a directory (or _folder_) on the file system.
  *
  * A Directory instance is an object holding a [path] on which operations can
- * be performed. The path to the directory can be [absolute] or [relative].
+ * be performed. The path to the directory can be [absolute] or relative.
  * You can get the parent directory using the getter [parent],
  * a property inherited from [FileSystemEntity].
  *
  * In addition to being used as an instance to access the file system,
  * Directory has a number of static properties, such as [systemTemp],
  * which gets the system's temporary directory, and the getter and setter
  * [current], which you can use to access or change the current directory.
  *
  * Create a new Directory object with a pathname to access the specified
  * directory on the file system from your program.
@@ skipping 282 matching lines @@
    * directories, files, and links.
    */
   List<FileSystemEntity> listSync(
       {bool recursive: false, bool followLinks: true});
 
   /**
    * Returns a human readable string for this Directory instance.
    */
   String toString();
 }