[analyzer] remove "auto-generated do not edit" comments

pkg/analyzer/lib/src/generated/testing/token_factory.dart

 // Copyright (c) 2014, 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 code was auto-generated, is not intended to be edited, and is subject to
-// significant change. Please see the README file for more information.
-
 library engine.testing.token_factory;
 
 import 'package:analyzer/src/generated/scanner.dart';
 
 /**
  * A set of utility methods that can be used to create tokens.
  */
 class TokenFactory {
   static Token tokenFromKeyword(Keyword keyword) =>
       new KeywordToken(keyword, 0);
 
   static Token tokenFromString(String lexeme) =>
       new StringToken(TokenType.STRING, lexeme, 0);
 
   static Token tokenFromType(TokenType type) => new Token(type, 0);
 
   static Token tokenFromTypeAndString(TokenType type, String lexeme) =>
       new StringToken(type, lexeme, 0);
 }