Add documentation comments for enum and enum values. Resynthesize in analyzer.

pkg/front_end/lib/src/fasta/source/stack_listener.dart

 // Copyright (c) 2016, 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 fasta.stack_listener;
 
 import 'package:kernel/ast.dart' show AsyncMarker, Expression;
 
 import '../deprecated_problems.dart' show deprecated_inputError;
 
@@ skipping 17 matching lines @@
   Block,
   BreakTarget,
   CascadeReceiver,
   Combinators,
   Comments,
   ConditionalUris,
   ConstructorInitializerSeparator,
   ConstructorInitializers,
   ConstructorReferenceContinuationAfterTypeArguments,
   ContinueTarget,
+  DocumentationComment,
   Expression,
   FieldInitializer,
   FormalParameters,
   FunctionBody,
   FunctionBodyAsyncToken,
   FunctionBodyStarToken,
   Identifier,
   IdentifierList,
   Initializers,
   Metadata,
@@ skipping 286 matching lines @@
     list.setRange(0, arrayLength, array);
     return list;
   }
 
   void _grow() {
     final List newTable = new List(array.length * 2);
     newTable.setRange(0, array.length, array, 0);
     array = newTable;
   }
 }