Add link to sample app as it is unfindable with the embedded url.

Author: Kent Walters

src/App.js

@@ -35,6 +35,7 @@ const App = () => {
       <br />
       <br />
       <Retool
+      // FYI: https://support.retool.com/apps/56f90c0c-379a-11ec-a25e-43838d4022ed/Ben/Sample%20React%20Retool
         url="https://support.retool.com/embedded/public/cb9e15f0-5d7c-43a7-a746-cdec870dde9a"
         data={data}
         height="700px"