make deprecated elements have low suggestion relevance

pkg/analysis_server/lib/src/services/completion/imported_computer.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.computer.dart.toplevel;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element,
     ElementKind;
@@ skipping 206 matching lines @@
         }
       }
     }
     if (typesOnly && element is! ClassElement) {
       return;
     }
 
     String completion = element.displayName;
     CompletionSuggestion suggestion = new CompletionSuggestion(
         CompletionSuggestionKind.INVOCATION,
-        relevance,
+        element.isDeprecated ? CompletionRelevance.LOW : relevance,
         completion,
         completion.length,
         0,
         element.isDeprecated,
         false);
 
     suggestion.element = newElement_fromEngine(element);
 
     DartType type;
     if (element is FunctionElement) {
@@ skipping 150 matching lines @@
           importElem.isDeprecated,
           false);
       LibraryElement lib = importElem.importedLibrary;
       if (lib != null) {
         suggestion.element = newElement_fromEngine(lib);
       }
       request.suggestions.add(suggestion);
     }
   }
 }