chore: update links to HTMLHint.com

Author: nschonni

index.html

@@ -23,7 +23,7 @@
         <a href="https://github.com/htmlhint/HTMLHint"><img style="position: absolute; top: 0; right: 0; border: 0;" src="img/forkme.png" alt="Fork me on GitHub"></a>
         <div class="masthead">
           <ul class="nav nav-pills pull-right">
-            <li class="active"><a href="https://htmlhint.io/">Home</a></li>
+            <li class="active"><a href="https://htmlhint.com/">Home</a></li>
             <li><a href="https://github.com/htmlhint/HTMLHint/wiki/About">About</a></li>
             <li><a href="https://github.com/htmlhint/HTMLHint/wiki/Usage">Usage</a></li>
             <li><a href="https://github.com/htmlhint/HTMLHint/wiki/Rules">Rules</a></li>
@@ -162,7 +162,7 @@ <h3>Other</h3>
         </div>
         <hr>
         <div class="footer">
-            <p>&copy; HTMLHint.io 2014-2018</p>
+            <p>&copy; HTMLHint.com 2014-2021</p>
         </div>
     </div>
     <script src="js/jquery-1.9.1.min.js"></script>