Point property for a Billboard.js chart
Arguments
- bb
- A - billboard- htmlwidgetobject.
- ...
- See https://naver.github.io/billboard.js/release/latest/doc/Options.html#.point 
Examples
# Set point size
billboarder() %>% 
  bb_scatterplot(data = iris, x = "Sepal.Length", y = "Sepal.Width", group = "Species") %>% 
  bb_axis(x = list(tick = list(fit = FALSE))) %>% 
  bb_point(r = 10)