Remove custom example plugin. (#25784)

docs/4.0/components/popovers.md

@@ -47,9 +47,10 @@ $(function () {
 
 ## Example
 
-{% example html %}
+{% capture example %}
 <button type="button" class="btn btn-lg btn-danger" data-toggle="popover" title="Popover title" data-content="And here's some amazing content. It's very engaging. Right?">Click to toggle popover</button>
-{% endexample %}
+{% endcapture %}
+{% include example.html content=example %}
 
 ### Four directions
 
@@ -102,9 +103,10 @@ For proper cross-browser and cross-platform behavior, you must use the `<a>` tag
 {% endcapture %}
 {% include callout.html content=callout type="danger" %}
 
-{% example html %}
+{% capture example %}
 <a tabindex="0" class="btn btn-lg btn-danger" role="button" data-toggle="popover" data-trigger="focus" title="Dismissible popover" data-content="And here's some amazing content. It's very engaging. Right?">Dismissible popover</a>
-{% endexample %}
+{% endcapture %}
+{% include example.html content=example %}
 
 {% highlight js %}
 $('.popover-dismiss').popover({
@@ -118,11 +120,12 @@ Elements with the `disabled` attribute aren't interactive, meaning users cannot
 
 For disabled popover triggers, you may also prefer `data-trigger="hover"` so that the popover appears as immediate visual feedback to your users as they may not expect to _click_ on a disabled element.
 
-{% example html %}
+{% capture example %}
 <span class="d-inline-block" data-toggle="popover" data-content="Disabled popover">
   <button class="btn btn-primary" style="pointer-events: none;" type="button" disabled>Disabled button</button>
 </span>
-{% endexample %}
+{% endcapture %}
+{% include example.html content=example %}
 
 ## Usage