update code style

Author: Jay2113

src/pages/[platform]/start/quickstart/nextjs-app-router-client-components/index.mdx

@@ -268,7 +268,7 @@ import { generateClient } from "aws-amplify/data";
 
 const client = generateClient<Schema>();
 
-export default function App() {
+export default function HomePage() {
 
   // highlight-start
   const { signOut } = useAuthenticator();
@@ -364,17 +364,17 @@ In the application client code, let's also render the username to distinguish di
 ```tsx title="app/page.tsx"
 // ... imports
 
-function App() {
+function HomePage() {
   // highlight-next-line
-  const user = useAuthenticator().user;
+  const { user, signOut } = useAuthenticator();
 
   // ...
 
   return (
     <main>
       // highlight-next-line
       <h1>{user?.signInDetails?.loginId}'s todos</h1>
-      {/* ... rest of the UI */}
+      {/* ... */}
     </main>
   )
 }