Unify the server and plugin versions of the generators

pkg/analysis_server/lib/src/utilities/change_builder_dart.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:async';
 
-import 'package:analysis_server/plugin/protocol/protocol.dart'
+import 'package:analysis_server/protocol/protocol_generated.dart'
     hide Element, ElementKind;
 import 'package:analysis_server/src/provisional/edit/utilities/change_builder_core.dart';
 import 'package:analysis_server/src/provisional/edit/utilities/change_builder_dart.dart';
 import 'package:analysis_server/src/services/correction/name_suggestion.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
 import 'package:analysis_server/src/utilities/change_builder_core.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 700 matching lines @@
   void _addSuperTypesAsSuggestions(DartType type, Set<DartType> alreadyAdded) {
     if (type is InterfaceType && alreadyAdded.add(type)) {
       addSuggestion(LinkedEditSuggestionKind.TYPE, type.displayName);
       _addSuperTypesAsSuggestions(type.superclass, alreadyAdded);
       for (InterfaceType interfaceType in type.interfaces) {
         _addSuperTypesAsSuggestions(interfaceType, alreadyAdded);
       }
     }
   }
 }