Fix ClosureRule comment (Issue 7893)

pkg/serialization/lib/serialization.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.
 
 /**
  * This provides a general-purpose serialization facility for Dart objects. A
  * [Serialization] is defined in terms of [SerializationRule]s and supports
  * reading and writing to different formats.
  *
  * Setup
@@ skipping 69 matching lines @@
  * minimum necessary information in [create] and do more of the work in
  * [setState].
  *
  * The other way to do this is not creating a subclass, but by using a
  * [ClosureRule] and giving it functions for how to create
  * the address.
  *
  *      addressToMap(a) => {"number" : a.number, "street" : a.street,
  *          "city" : a.city};
  *      createAddress(Map m) => new Address.create(m["number"], m["street"]);
- *      fillInAddress(Map m, Address a) => a.city = m["city"];
+ *      fillInAddress(Address a, Map m) => a.city = m["city"];
  *      var serialization = new Serialization()
  *        ..addRule(
  *            new ClosureRule(anAddress.runtimeType,
  *                addressToMap, createAddress, fillInAddress);
  *
  * In this case we have created standalone functions rather than
  * methods in a subclass and we pass them to the constructor of
  * [ClosureRule]. In this case we've also had them use maps rather than
  * lists for the state, but either would work as long as the rule is
  * consistent with the representation it uses. We pass it the runtimeType
@@ skipping 355 matching lines @@
   }
 }
 
 /**
  * An exception class for errors during serialization.
  */
 class SerializationException implements Exception {
   final String message;
   const SerializationException([this.message]);
 }