Show a list of shapes in scale_shape docs (#1578)

* Show a list of shapes in scale_shape docs

* Cleaned up shapes list

* cleanup shape example code

Author: steveharoz

R/scale-shape.r

@@ -24,6 +24,13 @@
 #'
 #' # Or for short:
 #' d %+% dsmall
+#'
+#' # Show a list of available shapes
+#' df_shapes <- data.frame(shape = 0:24)
+#' ggplot(df_shapes, aes(shape = shape)) +
+#'   geom_point(aes(shape = shape, x = 0, y = 0), size = 5, fill = 'red') +
+#'   scale_shape_identity() +
+#'   facet_wrap(~shape) + theme_void()
 scale_shape <- function(..., solid = TRUE) {
   discrete_scale("shape", "shape_d", shape_pal(solid), ...)
 }