Clarify github_pull() documentation (#640)

Co-authored-by: Jim Hester <james.f.hester@gmail.com>

NEWS.md

@@ -2,6 +2,7 @@
 
 * Using `remote_package_name.git2r_remote` and `remote_package_name.xgit_remote`, http responses returning an invalid `DESCRIPTION` or that redirect to another page will now fallback to return `NA` instead of throwing an error when trying to parse the unexpected content (#628, @dgkf).
 * Fix regex that breaks git protocol in `git_remote` (@niheaven #630).
+* Clarify `github_pull()` documentation (@ms609 #640).
 
 # remotes 2.4.0
 

R/install-github.R

@@ -34,7 +34,7 @@
 #' @examples
 #' \dontrun{
 #' install_github("klutometis/roxygen")
-#' install_github("wch/ggplot2")
+#' install_github("wch/ggplot2", ref = github_pull("142"))
 #' install_github(c("rstudio/httpuv", "rstudio/shiny"))
 #' install_github(c("hadley/httr@@v0.4", "klutometis/roxygen#142",
 #'   "r-lib/roxygen2@@*release", "mfrasca/r-logging/pkg"))
@@ -153,8 +153,10 @@ remote_metadata.github_remote <- function(x, bundle = NULL, source = NULL, sha =
 #' Use as `ref` parameter to [install_github()].
 #' Allows installing a specific pull request or the latest release.
 #'
-#' @param pull The pull request to install
+#' @param pull Character string specifying the pull request to install
 #' @seealso [install_github()]
+#' @examples
+#' github_pull("42")
 #' @rdname github_refs
 #' @export
 github_pull <- function(pull) structure(pull, class = "github_pull")