Fix comment for Uri encodeComponent.

sdk/lib/core/uri.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.core;
 
 /**
  * A parsed URI, as specified by RFC-3986, http://tools.ietf.org/html/rfc3986.
  */
 class Uri {
@@ skipping 1038 matching lines @@
       sb.write(first);
       sb.write(second);
     }
   }
 
   /**
    * Encode the string [component] using percent-encoding to make it
    * safe for literal use as a URI component.
    *
    * All characters except uppercase and lowercase letters, digits and
-   * the characters `!$&'()*+,;=:@` are percent-encoded. This is the
+   * the characters `-_.!~*'()` are percent-encoded. This is the
    * set of characters specified in RFC 2396 and the which is
    * specified for the encodeUriComponent in ECMA-262 version 5.1.
    *
    * When manually encoding path segments or query components remember
    * to encode each part separately before building the path or query
    * string.
    *
    * For encoding the query part consider using
    * [encodeQueryComponent].
    *
@@ skipping 565 matching lines @@
   void clear() {
     throw new UnsupportedError("Cannot modify an unmodifiable map");
   }
   void forEach(void f(K key, V value)) => _map.forEach(f);
   Iterable<K> get keys => _map.keys;
   Iterable<V> get values => _map.values;
   int get length => _map.length;
   bool get isEmpty => _map.isEmpty;
   bool get isNotEmpty => _map.isNotEmpty;
 }