Adding a Stringish type

Reviewed By: yungsters

Differential Revision: D7984925

fbshipit-source-id: b58bff2fa172f8127d70986accb45af1afca4d68

flow/Stringish.js

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) 2015-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.
+ *
+ * @flow
+ * @format
+ */
+
+// This type allows Facebook to internally Override
+// this type to allow our internationalization type which
+// is a string at runtime but Flow doesn't know that.
+declare type Stringish = string;