Add comment to UI extension to improve readability

Author: mraible

ui/extensions/hello/src/pages/home.js

@@ -16,6 +16,7 @@ function Home() {
   const [loading, setLoading] = useState(false);
   const [error, setError] = useState(null);
 
+  // Calls the 'hello' cloud function with the user's name and displays the response
   const fetchGreeting = async () => {
     if (!name.trim()) {
       setError("Please enter a name first");