feat(site): update demo code-block

site/src/pages/demo.html

@@ -79,7 +79,11 @@
     <main>
       <a href="/demo/about">{{ count }}</a>
       <div>
-        <my-hello-world data-name="{{name }}"></my-hello-world>
+        <my-hello-world id="my-hello" data-name="{{name }}"></my-hello-world>
+        <input
+          placeholder="Type your name here"
+          onkeyup="document.getElementById('my-hello').setAttribute('data-name', this.value)"
+        />
       </div>
       <code-block language="js">const name = "Nitro"</code-block>
       <p>some text: {{greeting}}</p>