update suggestion element return type to have type param

pkg/analysis_server/test/services/completion/prefixed_element_contributor_test.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 test.services.completion.invocation;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
@@ skipping 220 matching lines @@
     return computeFull((bool result) {
       assertSuggestClass('Future');
     });
   }
 
   test_libraryPrefix_deferred() {
     // SimpleIdentifier  PrefixedIdentifier  ExpressionStatement
     addTestSource('import "dart:async" deferred as bar; foo() {bar.^}');
     return computeFull((bool result) {
       assertSuggestClass('Future');
-      assertSuggestFunction('loadLibrary', 'void');
+      assertSuggestFunction('loadLibrary', 'Future<dynamic>');
     });
   }
 
   test_libraryPrefix_with_exports() {
     addSource('/libA.dart', 'library libA; class A { }');
     addSource('/libB.dart', 'library libB; export "/libA.dart"; class B { }');
     addTestSource('import "/libB.dart" as foo; main() {foo.^} class C { }');
     computeFast();
     return computeFull((bool result) {
       assertSuggestClass('B');
@@ skipping 397 matching lines @@
       assertNotSuggested('ms2');
       assertSuggestInvocationMethod('m', 'C2', null,
           relevance: DART_RELEVANCE_HIGH);
       assertNotSuggested('fi3');
       assertNotSuggested('fs3');
       assertNotSuggested('mi3');
       assertNotSuggested('ms3');
     });
   }
 }