Fix hints and clean-up obsolete comment syntax (TBR)

pkg/analysis_server/test/services/completion/dart/completion_contributor_util.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.
 
 import 'dart:async';
 
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_performance.dart';
 import 'package:analysis_server/src/services/completion/dart/completion_manager.dart'
@@ skipping 546 matching lines @@
           cs = s;
         } else {
           failedCompletion('expected exactly one $cs',
               suggestions.where((s) => s.completion == completion));
         }
       });
     }
     return cs;
   }
 
-  Future/*<E>*/ performAnalysis/*<E>*/(
-      int times, Completer/*<E>*/ completer) async {
+  Future<E> performAnalysis<E>(int times, Completer<E> completer) async {
     if (completer.isCompleted) {
       return completer.future;
     }
     // We use a delayed future to allow microtask events to finish. The
     // Future.value or Future() constructors use scheduleMicrotask themselves and
     // would therefore not wait for microtask callbacks that are scheduled after
     // invoking this method.
     return new Future.delayed(
         Duration.ZERO, () => performAnalysis(times - 1, completer));
   }
 
   void resolveSource(String path, String content) {
     addSource(path, content);
   }
 
   @override
   void setUp() {
     super.setUp();
     testFile = provider.convertPath('/completionTest.dart');
     contributor = createContributor();
   }
 }