rename completion source files to match content

pkg/analysis_server/test/services/completion/combinator_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.dart.combinator;
 
 import 'package:analysis_server/src/protocol.dart';
-import 'package:analysis_server/src/services/completion/combinator_computer.dart';
+import 'package:analysis_server/src/services/completion/combinator_contributor.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
 import 'package:unittest/unittest.dart';
 
 import '../../reflective_tests.dart';
 import 'completion_test_util.dart';
 
 main() {
   groupSep = ' | ';
   runReflectiveTests(CombinatorContributorTest);
 }
@@ skipping 101 matching lines @@
           kind: CompletionSuggestionKind.IDENTIFIER);
       assertSuggestFunctionTypeAlias('F2', null,
           false, DART_RELEVANCE_DEFAULT, CompletionSuggestionKind.IDENTIFIER);
       assertNotSuggested('C');
       assertNotSuggested('D');
       assertNotSuggested('X');
       assertNotSuggested('Object');
     });
   }
 }