Consider different check for RawInline formats?

[matthew-brett]

Thanks for Panflute - as ever - we are using it productively in with our book project.

However, we've run into a problem that the Quarto team think is a bug in Panflute:

quarto-dev/quarto-cli#7215 (comment)

To quote from that description:

This is a Panflute issue, where they're checking for valid formats for RawInlines, but Pandoc is emitting a format that it's not expecting.

Specifically, Panflute is not expecting to see a typst raw block. I believe any RawBlock format string is valid, and that Panflute should not be checking for a set of strings.

Is that possible - to do a more general check that will allow through such valid-but-as-yet-unknown-to-Panflute types?

(With pre-emptive apologies for the possibility that I have misunderstood the issue).