Create a qualitative legend. `legend_scale`` accepts scales listed in d3-scale.
legend_sequential(
variable_name,
legend_scale = "scaleLinear",
color_low = "white",
color_high = "green",
color_no_data = "lightgrey"
)
string, name of the variable of this legend.
string, type of legend scale, must be the name of a d3 scale. Default: "scaleLinear".
string, color for the lowest value of the legend.
string, color for the highest value of the legend.
string, color for no data entries.