Fixes apostrophe in less.html

docs/less.html

@@ -73,7 +73,7 @@
       <div class="row">
         <div class="span4">
           <h3>Why LESS?</h3>
-          <p>Bootstrap is made with LESS at it's core, a dynamic stylesheet language created by <a href="http://cloudhead.io">Alexis Sellier</a>. It makes developing systems-based CSS faster, easier, and more fun.</p>
+          <p>Bootstrap is made with LESS at its core, a dynamic stylesheet language created by <a href="http://cloudhead.io">Alexis Sellier</a>. It makes developing systems-based CSS faster, easier, and more fun.</p>
         </div>
         <div class="span4">
           <h3>What's included?</h3>