Bug cleanup: change String.trim comment to be less ambiguous.

lib/core/string.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
 /**
  * The String class represents character strings. Strings are
  * immutable. A string is represented by a list of 32-bit Unicode
  * scalar character codes accessible through the [charCodeAt] or the
  * [charCodes] method.
  */
 interface String
@@ skipping 59 matching lines @@
    */
   String concat(String other);
 
   /**
    * Returns a substring of this string in the given range.
    * [startIndex] is inclusive and [endIndex] is exclusive.
    */
   String substring(int startIndex, [int endIndex]);
 
   /**
-   * Returns a new string where leading and trailing whitespaces of
-   * this string have been removed, or returns this string if it does
-   * not have leading and trailing whitespaces.
+   * Removes leading and trailing whitespace from a string. If the
+   * string contains leading or trailing whitespace a new string with
+   * no leading and no trailing whitespace is returned. Otherwise, the
+   * string itself is returned.
    */
   String trim();
 
   /**
    * Returns whether this string contains [other] starting
    * at [startIndex] (inclusive).
    */
   bool contains(Pattern other, [int startIndex]);
 
   /**
@@ skipping 29 matching lines @@
    * where all characters  are made lower case. Returns [:this:] otherwise.
    */
   String toLowerCase();
 
   /**
    * If this string is not already all uper case, returns a new string
    * where all characters are made upper case. Returns [:this:] otherwise.
    */
   String toUpperCase();
 }