show_news() only checks {pkg}/NEWS

[arcresu]

The show_news() function is hard-coded to check only for NEWS in a package directory:

devtools/R/show-news.R

Line 10 in 7cc2bdf

news_path <- path(pkg$path, "NEWS")

However (from the docs of utils::news()):

[...] it is attempted to read its news in structured form from files ‘inst/NEWS.Rd’, ‘NEWS.md’ (since R version 3.6.0, needs packages commonmark and xml2 to be available), ‘NEWS’ or ‘inst/NEWS’ (in that order).

This means that if a NEWS.md file exists, for example, there's a confusing error:

> show_news()
Error in `show_news()`:
! No NEWS found
Run `rlang::last_error()` to see where the error occurred.

It would be nice if show_news() could use the same search path as utils::news() does.

[jennybc]

If you'd like to make a PR, you could adapt related logic from build_readme():

devtools/R/build-readme.R

Lines 53 to 67 in 45354cf

	build_readme <- function(path = ".", quiet = TRUE, ...) {
	pkg <- as.package(path)
	regexp <- paste0(path_file(pkg$path), "/(inst/)?readme[.]rmd")
	readme_path <- path_abs(dir_ls(pkg$path, ignore.case = TRUE, regexp = regexp, recurse = 1, type = "file"))
	if (length(readme_path) == 0) {
	cli::cli_abort("Can't find {.file README.Rmd} or {.file inst/README.Rmd}.")
	}
	if (length(readme_path) > 1) {
	cli::cli_abort("Can't have both {.file README.Rmd} and {.file inst/README.Rmd}.")
	}
	build_rmd(readme_path, path = path, quiet = quiet, ...)
	}