Update edit.importElements response data to support part files

pkg/analysis_server/test/integration/support/protocol_matchers.dart

 // Copyright (c) 2017, 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.
 //
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
 /**
  * Matchers for data types defined in the analysis server API
@@ skipping 2033 matching lines @@
  * }
  */
 final Matcher isEditImportElementsParams = new LazyMatcher(() =>
     new MatchesJsonObject("edit.importElements params",
         {"file": isFilePath, "elements": isListOf(isImportedElements)}));
 
 /**
  * edit.importElements result
  *
  * {
- *   "edits": List<SourceEdit>
+ *   "edit": SourceFileEdit
  * }
  */
 final Matcher isEditImportElementsResult = new LazyMatcher(() =>
     new MatchesJsonObject(
-        "edit.importElements result", {"edits": isListOf(isSourceEdit)}));
+        "edit.importElements result", {"edit": isSourceFileEdit}));
 
 /**
  * edit.isPostfixCompletionApplicable params
  *
  * {
  *   "file": FilePath
  *   "key": String
  *   "offset": int
  * }
  */
@@ skipping 560 matching lines @@
  * server.status params
  *
  * {
  *   "analysis": optional AnalysisStatus
  *   "pub": optional PubStatus
  * }
  */
 final Matcher isServerStatusParams = new LazyMatcher(() =>
     new MatchesJsonObject("server.status params", null,
         optionalFields: {"analysis": isAnalysisStatus, "pub": isPubStatus}));