Bands in plot.spar.cv for plot_type = "Val_numAct"

[lauravana]

Should we also include bands for when plot_type = "Val_numAct"?

spar_cv <- spar.cv(example_data$x, example_data$y,
                       nummods = c(5, 10, 20, 50),
                       measure = "mse")
plot(spar_cv, plot_type = "Val_numAct")