Update file_touch documentation

Per #169, this _does_ create the file if it does not exist.

R/file.R

@@ -227,16 +227,15 @@ file_move <- function(path, new_path) {
 
 #' Change file access and modification times
 #'
-#' Unlike the touch POSIX utility this does not create the file if it does not
-#' exist. Use [file_create()] to do this if needed.
+#' Like the touch POSIX utility this will create the file if it does not
+#' exist.
 #'
 #' @template fs
 #'
 #' @param access_time,modification_time The times to set, inputs will be
 #'   coerced to [POSIXct] objects.
 #' @examples
 #' \dontshow{.old_wd <- setwd(tempdir())}
-#' file_create("foo")
 #' file_touch("foo", "2018-01-01")
 #' file_info("foo")[c("access_time", "modification_time", "change_time", "birth_time")]
 #' \dontshow{setwd(.old_wd)}