fix: move ending tag

Author: CBID2

2-structure/09_family_tree.html

@@ -10,13 +10,12 @@
     <<h1>The Simpsons</h1>
     <p>🏡 Hometown: Springfield, IL</p>
     <ul>
-      <li>Homer & Marge Simpson
+      <li>Homer & Marge Simpson</li>
         <ul>
           <li>Bart Simpson</li>
           <li>Lisa Simpson</li>
           <li>Maggie Simpson</li>
         </ul>
-      </li>
       <li>Patty Bouvier (Twin)</li>
       <li>Selma Bouvier (Twin)</li>
     </ul>