expose `stat` argument in geom_vline and geom_hline?

[EvaMaeRey]

I think it would be nice to expose the stat argument in geom_vline and geom_hline. These are rare exceptions where you aren't be able to access the Geom from the analogous user-facing function geom_*(), like geom_segment(stat = StatManual), geom_point(stat = StatNewCustom)...

The following modification might be in the right direction. The stat change does raise some more questions of exposing position, and other arguments additionally.

geom_vline <- function(mapping = NULL, data = NULL,
                       ...,
                       xintercept,
                       na.rm = FALSE,
                       show.legend = NA,
                       stat = "identity") {                   #<<<< new exposed argument

  # Act like an annotation
  if (!missing(xintercept)) {
    # Warn if supplied mapping and/or data is going to be overwritten
    if (!is.null(mapping)) {
      cli::cli_warn("{.fn geom_vline}: Ignoring {.arg mapping} because {.arg xintercept} was provided.")
    }
    if (!is.null(data)) {
      cli::cli_warn("{.fn geom_vline}: Ignoring {.arg data} because {.arg xintercept} was provided.")

  # add a warning about stat being ignored if xintercept is provided ?
  
    }

    data <- data_frame0(xintercept = xintercept)
    mapping <- aes(xintercept = xintercept)
    show.legend <- FALSE
  }

  layer(
    data = data,
    mapping = mapping,
    stat = stat,                   #<<<< not fixed
    geom = GeomVline,
    position = PositionIdentity,
    show.legend = show.legend,
    inherit.aes = missing(xintercept),       #<<<< This change or similar
    params = rlang::list2(
      na.rm = na.rm,
      ...
    )
  )