refactor ContributionSorter to use new API

pkg/analysis_server/lib/src/services/completion/optype.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 services.completion.dart.optype;
 
-import 'package:analysis_server/src/services/completion/completion_target.dart';
+import 'package:analysis_server/completion/dart/completion_target.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 
 /**
  * An [AstVisitor] for determining whether top level suggestions or invocation
  * suggestions should be made based upon the type of node in which the
  * suggestions were requested.
  */
 class OpType {
   /**
@@ skipping 623 matching lines @@
   void visitVariableDeclarationStatement(VariableDeclarationStatement node) {}
 
   @override
   void visitWhileStatement(WhileStatement node) {
     if (identical(entity, node.condition)) {
       optype.includeReturnValueSuggestions = true;
       optype.includeTypeNameSuggestions = true;
     }
   }
 }