add callout for rn web

Author: josefaidt

src/pages/[platform]/start/quickstart/index.mdx

@@ -2650,7 +2650,13 @@ Before you get started, make sure you have the following installed:
 
 This Quickstart guide will walk you through how to build a Todo application for Android or iOS using [Expo](https://expo.dev/)'s TypeScript template.
 
-  <Callout>
+<Callout warning>
+
+**Warning:** React Native for Web is currently not supported. We are working towards official support, and are tracking the progress in [issue #13918 on GitHub](https://github.com/aws-amplify/amplify-js/issues/13918)
+
+</Callout>
+
+<Callout>
 
 Amplify now requires native modules not available through the Expo SDK. As a result, Expo Go is no longer supported but you should still be able to use Expo. [Learn more about dropping support for Expo Go in Amplify v6](/gen1/react-native/build-a-backend/troubleshooting/migrate-from-javascript-v5-to-v6/).