docs: 📚️added missing selector function in async components (#133)

docs/building-blocks/async-components.md

@@ -18,12 +18,17 @@ export const HomePage = lazyLoad(
 In this case, the app won't show anything while loading your component. You can, however, make it display a custom loader with:
 
 ```ts
-import * as React from 'react';
+import React from 'react';
 import { lazyLoad } from 'utils/loadable';
 
-export const HomePage = lazyLoad(() => import('./index'), {
-  fallback: <div>Loading...</div>,
-});
+export const HomePage = lazyLoad(
+  () => import('./index'),
+  module => module.HomePage,
+  {
+    fallback: <div>Loading...</div>,
+  }
+);
 ```
 
+Make sure to rename your `Loadable.ts` file to `Loadable.tsx`.
 This feature is built into the boilerplate using React's `lazy` and `Suspense` features.