Update index-FINISHED.html

I found that if you don't call the parentNode the value of this point to the mole and the class was added to the hole. BTW, the remove class didn't worked.

Author: PabloCarmona

30 - Whack A Mole/index-FINISHED.html

@@ -76,7 +76,7 @@ <h1>Whack-a-mole! <span class="score">0</span></h1>
   function bonk(e) {
     if(!e.isTrusted) return; // cheater!
     score++;
-    this.classList.remove('up');
+    this.parentNode.classList.remove('up');
     scoreBoard.textContent = score;
   }