remove docgen source and targets from build

pkg/docgen/lib/src/models/annotation.dart

Index: pkg/docgen/lib/src/models/annotation.dart
diff --git a/pkg/docgen/lib/src/models/annotation.dart b/pkg/docgen/lib/src/models/annotation.dart
deleted file mode 100644
index 766939cc932478e5aba4ba7844f71815c375ca0a..0000000000000000000000000000000000000000
--- a/pkg/docgen/lib/src/models/annotation.dart
+++ /dev/null
@@ -1,32 +0,0 @@
-// 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 docgen.models.annotation;
-
-import '../exports/source_mirrors.dart';
-
-import '../library_helpers.dart';
-
-import 'library.dart';
-import 'mirror_based.dart';
-
-import 'dart:mirrors';
-
-/// Holds the name of the annotation, and its parameters.
-class Annotation extends MirrorBased<ClassMirror> {
-  /// The class of this annotation.
-  DeclarationMirror mirror;
-  final Library owningLibrary;
-  List<String> parameters;
-
-  Annotation(this.owningLibrary, this.mirror,
-             [List<String> this.parameters = const <String>[]]);
-
-  Map toMap() => {
-    'name': owningLibrary.packagePrefix +
-        getDocgenObject(mirror, owningLibrary).docName,
-    'parameters': parameters
-  };
-}
-