Remove more libraries directives from server

pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart

Index: pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart
diff --git a/pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart b/pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart
index 146e6c065c976cbc51cd81f5a9401ba5ee8a83c8..ffcc1b97fb59e8d91f8434af2bdd1f3d0e0bc74f 100644
--- a/pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart
+++ b/pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart
@@ -2,8 +2,6 @@
 // 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 analysis_server.plugin.edit.assist.assist_dart;
-
 import 'dart:async';
 
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';