plot_points method name is confusing

[smcguire-cmu]

The inspection method plot_points is confusing in name and axes label. The name implies plotting actual points, not the density of points at the histogram order, and there is no axes label saying what the colors are plotting. And the numbers on the colorbar are not so useful (number of points per histogram order healpix pixel)

[delucchi-cmu]

I'd suggest having the plot title something like f"Number of points in each order {order} pixel"

[nevencaplar]

Add the name should be something like plot_density_pixel