I’m using knitr::rmarkdown (but knitr::knitr does the same) as my VignetteEngine. I then build my package vignette using devtools::build_vignettes().
This works, but only creates HTML and R output files in inst/doc. What I want is a Markdown output file, since only that can be displayed directly within the Github project pages (for HTML files, Github shows the source and for Rmd files it shows a rendered output but — obviously — without executing the R blocks).
I’ve tried finding out how to specify the output for custom VignetteEngines and I think that it should be possible (after all, other packages use this to build PDF vignettes, at a minimum) but I cannot find a way of doing this via devtools::build_vignettes. Is there no way around building the vignette manually (i.e. via knitr::knit or similar mechanisms that ignore the VignetteBuilder directives)?
I can’t find relevant information in the documentation/source either.