changes the order of the close btn on alerts to improve accecibility

docs/4.0/components/alerts.md

@@ -59,10 +59,10 @@ You can see this in action with a live demo:
 
 {% example html %}
 <div class="alert alert-warning alert-dismissible fade show" role="alert">
+  <strong>Holy guacamole!</strong> You should check in on some of those fields below.
   <button type="button" class="close" data-dismiss="alert" aria-label="Close">
     <span aria-hidden="true">&times;</span>
   </button>
-  <strong>Holy guacamole!</strong> You should check in on some of those fields below.
 </div>
 {% endexample %}