Feature: recursive citeproc?

[jdutant]

There some demand for recursive citations, i.e. handling \cite commands within the bibliographies themselves, usually in the BibTeX note field. See this exchange on pandoc-discuss. Would you be interested in a PR adding this?

I've written a recursive citeproc filter that we use in the journal dialectica. I'm considering updating it for Quarto, but I'd be glad to contribute to section-bibliographies and multibib and use one of these instead.

I'd try to make the addition as lightweight as possible when no recursion is needed by first scanning the first citeproc pass's output with a filter {{ Citation = function(elem) has_citations = true end }}.