chore(v2): add Facebook copyright headers (#1067)

v2/lib/load/docs/order.js

@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 // build the docs meta such as next, previous, category and sidebar
 
 module.exports = function createOrder(allSidebars = {}) {