add examples for facet_title_horizontal() and similar functions

[chelseadickens]

Is it possible to add examples and more details about what facet_title_horizontal(), facet_title_left_horizontal(), and facet_title_right_horizontal() are supposed to do?

Thanks!

library(ggdist)
library(tidyverse)

df <- tibble(
  h = c(0,1,1,0, 0,2,2,0, 0,4/3,4/3,0, 0,1,1,0, 0,1.25,1.25,0, 0,.5,.5,0),
  x = c(0,1,4,5, 4,5,6,7, 6,7,9,10, 11,12,15,16, 1,2,4.2,5.2, 4,5,12,13),
  y = rep(c("a", "b", "a", "a", "b", "a"), each = 4),
  group = rep(c("c", "c", "d", "d", "c", "c"), each = 4),
  panel = rep(c("e", "e", "e", "e", "f", "f"), each = 4),
  name  = rep(c(1,    2, "3a","3b",  4,   5),  each = 4)
)

df_group = df %>%
  summarise(x = mean(x), .by = c(name, group, panel, y))


p2 <- function(){
  theme_set(facet_title_horizontal())
  fig = df %>%
    ggplot(aes(x = x, y = y, fill = group, thickness = h)) +
    geom_slab(color = "gray25", alpha = 0.75) +
    scale_y_discrete(expand = expansion(add = 0.1)) +
    scale_fill_brewer(palette = "Set2") +
    facet_grid(cols = vars(panel), labeller = "label_both") +
    labs("geom_slab() with default thickness scaling") 
  return(fig)
}

p2()