update .gitignore in vignettes folder with use_vignette()? #35
Description
(migrated from r-lib/devtools#1547)
To ignore .R and .html files generated when knitting .Rmd documents. This is desired because calls to e.g.
devtools::document(roclets = "vignette")
will drop the generated .R and .html files within the vignettes folder after completion. Note that RStudio users can opt-in to having this roclet run on Build and Reload within the IDE, so it's likely that such users will have these files sitting in the vignettes folder after a package build.