fix(combobox): Visually nest group items properly

[driskull]

Related Issue: #6384

Summary

Fix css for nesting group combobox items.

[driskull]

I can haz review? :)

[jcfranco]

Code changes LGTM!

@ashetland Can you review the visual diffs?

Good to merge once ☝️ approveth.

[ashetland]

It looks like when items get slotted into an item-group, the var --calcite-combobox-item-spacing-indent-multiplier gets bumped by +1: what is 0, 1, 2... when not in a group becomes 1, 2, 3... when in a group. This bumping of the multiplier isn't ideal and complicates the hierarchical relationships when item-groups are used. Is it possible to change this behavior of item-group?

[driskull]

@ashetland isn't that what the issue is asking for? item-groups should provide nesting indentation?

[driskull]

This PR does make it look how it did previously.

[ashetland]

Thanks @driskull, you're totally right. This PR fixes the behavior of nesting groups. Should the other behavior fix be logged as its own issue? Sometimes we've been making little fixes like this as we catch them, but maybe that's not the best practice. Happy to log a separate issue if that's the preferred approach.

[driskull]

Should the other behavior fix be logged as its own issue

Yes, definitely. Otherwise we get scope creep

[ashetland]

Awesome. Approving now. 🚀