Missing documentation of the meaning of errorbars in cat_plot

[NilsPetras]

Greetings!

When using cat_plot, I failed to understand the meaning of the errorbars. Depending on the field (mine is psychology) it might not be obvious what errorbars should represent (SE, SD, 95% CI, 99% CI, ...). Even from looking into the function's code it is not obvious how the errorbars are computed. It would be very useful to have a comment on that in the package documentation.