Remove more libraries directives from server

pkg/analysis_server/lib/src/services/completion/dart/combinator_contributor.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.contributor.dart.combinator;
-
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart'
     hide Element, ElementKind;
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 
 /**
@@ skipping 21 matching lines @@
                 false,
                 false,
                 request.ideOptions);
         library.visitChildren(builder);
         return builder.suggestions;
       }
     }
     return EMPTY_LIST;
   }
 }