Visual editor mode snafus

[apreshill]

Trying to include a single image:

::: {.embed-right}
![mycology illustration](featured.jpg)
:::

<div class="embed-right">
![mycology illustration](featured.jpg)
</div>

{{< figure src="featured.jpg" alt="mushrooms" caption="Illustration by Beatrix Potter" >}}

If I flip on visual editor mode, <div class="embed-right"> becomes this: ::: {.embed-right} and renders with the dots:

The figure shortcode works well but doesn't show a preview in the visual editor. It would be great to be able to write blog posts well with the visual editor.