Fix ordering

Author: jcollins-g

lib/src/model/model.dart

@@ -7,12 +7,12 @@ export 'canonicalization.dart';
 export 'categorization.dart';
 export 'category.dart';
 export 'class.dart';
-export 'documentation_comment.dart';
 export 'constructor.dart';
 export 'container.dart';
 export 'container_member.dart';
 export 'documentable.dart';
 export 'documentation.dart';
+export 'documentation_comment.dart';
 export 'dynamic.dart';
 export 'enclosed_element.dart';
 export 'enum.dart';