bug: fenced divs with non-existent components /sometimes/ work

[Joshua Horowitz]

It looks like a fenced div with a made-up component name creates a div with that name as a class. Ex:

::: my-component
Text
:::

compiles to

<div class="my-component">
Text
</div>

That's nice. However, adding a class, like

::: my-component {.my-class}
Text
:::

breaks this. (It just outputs some <p>s and w/e.)

This is despite the fact that

::: {.my-component .my-class}
Text
:::

compiles to

<div class="my-component my-class">
Text
</div>

just fine.

(This behavior is confusing. I stumbled onto the ::: my-component notation early on, liked it, and was quite confused when it failed to accept classes.)