clarify attribute change example

Sascha Schulz

2024-02-05 904d9655997b1cb46bb8044843465c8045092af8

 index.html

@@ -3608,6 +3608,13 @@
               <section>
                  <h3>Auf Attribute reagieren</h3>
                  <pre>
                     <code class=html data-trim data-line-numbers>
                        <script type="text/template">
                           <hello-world my-attribute="a"></hello-world>
                        </script>
                     </code>
                  </pre>
                  <pre>
                     <code class="js" data-trim data-line-numbers="2|8-10">
                        <script type="text/template">
                           class HelloWorldComponent extends HTMLElement {