Attributes on paragraphs do not get carried over to pandoc AST

[calebeby]

If I use pandoc directly:

{.class-name}
hello

results in a wrapper div with the class attached, and the paragraph inside the div.

If I use djot.js djot.toPandoc(djot.parse(...)), only a paragraph is returned, without the attribute.

[jgm]

I'm open to changes to the pandoc module that add these wrapper divs and spans, as pandoc does.