bar widths and categoryarray

[nicolaskruchten]

In this pen https://codepen.io/nicolaskruchten/pen/eYvbyzJ I believe the bars should not overlap the "b" category.

Per #5072 (comment) I think that on categorical axes, the bar "span" (i.e. the width before taking into account bargap/bargroupgap) should be 1 always, not just when using overlay.

Note: this should apply to box and violin as well.