Correct typo in banner.html

added missing "to"

Author: EJLearner

_includes/banner.html

@@ -100,7 +100,7 @@ <h2>
         </div>
         <div class="callouts">
             <div id="guide" class="call"><a href="{{site.github.url}}/guide"><span class="icon"></span>
-                <big>Getting Started</big><small>Learn how install and use Chai through a series of guided walkthroughs.</small></a>
+                <big>Getting Started</big><small>Learn how to install and use Chai through a series of guided walkthroughs.</small></a>
                 <div class="bg"></div>
             </div>
             <div id="api" class="call"><a href="{{site.github.url}}/api"><span class="icon"></span>