docs: a nice example for set_blanket

[davidhodge931]

set_blanket(
  mode = light_mode_t(
    axis_line_colour = "#646464",
    panel_grid_colour = "#d1d1d1",
    panel_background_fill = "#f2f2f2",
    axis_line_linewidth = 0.75 / 2.835, #conversion from pts to mm
    panel_grid_linewidth = 0.75 / 2.835, #conversion from pts to mm
  ) + 
    theme(legend.title = element_blank()) +
    theme(axis.ticks.length.y = element_line(colour = "transparent")),
  geom_colour = grey,
  col_palette_d = c("#00b7cb", "#cd138c", "#6c4199", "#f16a00"),
)