Remove unintentional dependency on analysis_server

pkg/analyzer_plugin/lib/src/utilities/change_builder/change_builder_core.dart

 // Copyright (c) 2017, 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/protocol/protocol_generated.dart';
 import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer_plugin/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 
 /**
  * A builder used to build a [SourceChange].
  */
 class ChangeBuilderImpl implements ChangeBuilder {
   /**
    * The end-of-line marker used in the file being edited, or `null` if the
    * default marker should be used.
    */
@@ skipping 303 matching lines @@
   @override
   void write(String string) {
     editBuilder.write(string);
   }
 
   @override
   void writeln([String string]) {
     editBuilder.writeln(string);
   }
 }