Rename Error to RequestError in analysis server API.

pkg/analysis_server/tool/spec/api.dart

Index: pkg/analysis_server/tool/spec/api.dart
diff --git a/pkg/analysis_server/tool/spec/api.dart b/pkg/analysis_server/tool/spec/api.dart
index 0c660a7f9d45acb85c762c879056bca73057736a..98a9e7100a8a36298383d51aea80df88dbb62a81 100644
--- a/pkg/analysis_server/tool/spec/api.dart
+++ b/pkg/analysis_server/tool/spec/api.dart
@@ -284,9 +284,13 @@ class Request extends ApiNode {
    * "error" fields.
    */
   TypeDecl get responseType {
-    List<TypeObjectField> fields = [new TypeObjectField('id', new TypeReference(
-        'String', null), null), new TypeObjectField('error', new TypeReference('Error',
-        null), null, optional: true)];
+    List<TypeObjectField> fields = [
+        new TypeObjectField('id', new TypeReference('String', null), null),
+        new TypeObjectField(
+            'error',
+            new TypeReference('RequestError', null),
+            null,
+            optional: true)];
     if (result != null) {
       fields.add(new TypeObjectField('result', result, null));
     }