Remove the markdownify call, and instead rely on Hugo's proper syntax; {{% callout %}} when we want to the content to be rendered.
This allows for stuff like:
{{% callout info %}}
##### I'm an info callout!
.foo {
color: #fff;
}
{{< example >}}
<div class="alert alert-warning alert-dismissible fade show" role="alert">
<strong>Holy guacamole!</strong> You should check in on some of those fields below.
<button type="button" class="btn-close" data-dismiss="alert" aria-label="Close"></button>
</div>
{{< /example >}}
{{% /callout %}}Preview: https://deploy-preview-31802--twbs-bootstrap.netlify.app/