Use hyperlink in `warn_roxy_tag()` + `warn_roxy_block()`

[hadley]

Something like this:

warn_roxy_tag <- function(tag, message, ...) {
  link <- cli::style_hyperlink(
    paste0(basename(tag$file), ":", tag$line),
    paste0("file://", tag$file),
    params = c(line = tag$line, col = 1)
  )

  message[[1]] <- paste0(
    "[", link, "]", " @", tag$tag, " ",
    if (is.null(tag$raw)) ("(automatically generated) "),
    message[[1]]
  )
  cli::cli_warn(message, ..., .envir = parent.frame())
}