Remove custom example plugin. (#25784)

docs/4.0/utilities/image-replacement.md

@@ -21,6 +21,7 @@ Utilize the `.text-hide` class or mixin to help replace an element's text conten
 
 Use the `.text-hide` class to maintain the accessibility and SEO benefits of heading tags, but want to utilize a `background-image` instead of text.
 
-{% example html %}
+{% capture example %}
 <h1 class="text-hide" style="background-image: url('/assets/brand/bootstrap-solid.svg'); width: 50px; height: 50px;">Bootstrap</h1>
-{% endexample %}
+{% endcapture %}
+{% include example.html content=example %}