Clean up hints after a new hint was introduced

pkg/analyzer/lib/src/generated/parser.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.
 
 library analyzer.src.generated.parser;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/src/dart/ast/ast.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart';
-import 'package:analyzer/src/generated/engine.dart'
-    show AnalysisEngine, AnalysisOptionsImpl;
+import 'package:analyzer/src/generated/engine.dart' show AnalysisEngine;
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/generated/shared_messages.dart'
     as shared_messages;
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_collection.dart' show TokenMap;
 import 'package:analyzer/src/generated/utilities_dart.dart';
 
 export 'package:analyzer/src/dart/ast/utilities.dart' show ResolutionCopier;
@@ skipping 9927 matching lines @@
    */
   const ParserErrorCode(String name, String message, [String correction])
       : super(name, message, correction);
 
   @override
   ErrorSeverity get errorSeverity => ErrorSeverity.ERROR;
 
   @override
   ErrorType get type => ErrorType.SYNTACTIC_ERROR;
 }