Fix spelling mistake

Author: lulunac27a

index.html

@@ -17,7 +17,7 @@ <h1>Rate Our Service</h1>
             <span class="star" data="4" onclick="changeRating(4)">&#9733;</span>
             <span class="star" data="5" onclick="changeRating(5)">&#9733;</span>
         </div>
-        <!--button to sumbit rating--><button type="submit" id="submit-button">
+        <!--button to submit rating--><button type="submit" id="submit-button">
             Submit Rating
         </button>
         <div id="rating-output"></div>