When updating the demo app there are CSS styles and snippets that can help you out. Below are some examples.
<Label StyleClass="code">
{{ '<Rock:Image Source="https://yourserver.com/photo.jpg" />' | XamlWrap }}
</Label>
<Label StyleClass="code">
{% capture source %}<Button Text="Action Name"
StyleClass="btn, btn-primary-outline" />{% endcapture %}{{ source | XamlWrap }}</Label>