Inspector: make `next-sibling` work over atoms

[vemv]

It currently only works over sequential things - not atoms wrapping those.

[alexander-yakushev]

Does this mean navigating over a list of atoms, or an atom of list?

[vemv]

atom of list

[alexander-yakushev]

I just checked, this already works with the current sibling implementation on master.

[vemv]

Awesome! Then it would be a matter of making sure there are specific tests for it

[alexander-yakushev]

Just in case – this is not fully fixed yet. It works if the list inside atom was bigger than page size, so we rendered a collapsed value that the user first clicked, then clicked one of the items, then started prev/nexting it. But if we rendered an expanded list on the Atom view, and the user clicked from there, then prev/next doesn't work. Fixing this requires rethinking path construction yet again. This is in my backlog.