Fix modal example - remove container class

docs/documentation/components/modal.html

@@ -39,10 +39,8 @@ doc-subtab: modal
 {% highlight html %}
 <div class="modal">
   <div class="modal-background"></div>
-  <div class="modal-container">
-    <div class="modal-content">
-      <!-- Any other Bulma elements you want -->
-    </div>
+  <div class="modal-content">
+    <!-- Any other Bulma elements you want -->
   </div>
   <button class="modal-close"></button>
 </div>