Use callout without custom Jekyll plugin.

docs/4.0/getting-started/javascript.md

@@ -32,10 +32,11 @@ Alternatively, to target a specific plugin, just include the plugin's name as a
 $(document).off('.alert.data-api')
 {% endhighlight %}
 
-{% callout warning %}
+{% capture callout %}
 ##### Escaping selectors
 If you use special selectors, for example: `collapse:Example`, be sure to escape them, because they'll be passed through jQuery.
-{% endcallout %}
+{% endcapture %}
+{% include callout.html content=callout type="warning" %}
 
 ## Events
 
@@ -119,11 +120,12 @@ $.fn.tooltip.Constructor.VERSION // => "{{ site.current_version }}"
 
 Bootstrap's plugins don't fall back particularly gracefully when JavaScript is disabled. If you care about the user experience in this case, use [`<noscript>`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/noscript) to explain the situation (and how to re-enable JavaScript) to your users, and/or add your own custom fallbacks.
 
-{% callout warning %}
+{% capture callout %}
 ##### Third-party libraries
 
 **Bootstrap does not officially support third-party JavaScript libraries** like Prototype or jQuery UI. Despite `.noConflict` and namespaced events, there may be compatibility problems that you need to fix on your own.
-{% endcallout %}
+{% endcapture %}
+{% include callout.html content=callout type="warning" %}
 
 ## Util