migrate to pandoc-citeproc for references

[maxheld83]

as I understand, most other rmarkdown formats support citations via pandoc-citeproc, which has a bunch of advantages:

• established syntax/functionality
• pretty good bibtex parser (no problems such as in processing protection of bibtex titles is displayed incorrectly #24)
• arbitrary styles via the CSL standard (as also raised in support different reference section styling #36)

@jjallaire mentioned in #24 that radix currently uses distill, which in turn uses some js bibtex parser, which might be hard to disentangle.

I'm wondering whether it might be possible/might make sense to just ignore that part of distill, and do the usual rmarkdown pandoc-citeproc dance.

I'm in no position to say whether this would sit well with the rest of distill (does it do any additional black magic to citations?).
I guess the CSS would have to change a bit to retain the hover-citations (which are great).

If so, I might try to take a whack at this.

I just think it'd be a great benefit to rmarkdown users if all rmarkdown formats behave roughly the same when it comes to these features wrapped from pandoc.

[jjallaire]

Distill does quite a bit with citations so I think it would take a decent amount of effort to replicate this. Roughly you'd need to do this:

1. Don't write the Distill bibliography: https://github.com/rstudio/radix/blob/master/R/appendices.R#L14-L22

2. Don't convert citations to <d-cite>: https://github.com/rstudio/radix/blob/master/inst/rmarkdown/templates/radix_article/resources/distill.html#L532-L539

That would effectively disable what Distill does now. You'd then want to reproduce both the production of the bibliography appendix as well as the Distill JavaScript/CSS for inline citations. I'm not sure exactly where that is in Distill but I see these references in the Distill source code to the hover_site() function: https://github.com/distillpub/template/search?utf8=%E2%9C%93&q=hover_cite&type=

This is a rough summary, there may be other devil in the details here that I'm not aware of. Definitely not a simple project, but certainly do-able.

[jjallaire]

I just pushed a change that should address this (we now use pandoc to generate the bibliography rather than the distill framework): e8585bc

You can install this with remotes::install_github("rstudio/distill")