Collapsing on leaf node could act on its parent on some cases

[przepompownia]

It's possible that is litee-specific issue.

Expected: if the current node is a leaf or a closed tree, I would like to collapse its parent (in the example, arctgx#grep#grep).

Actual: nothing happens. To close I have to go to the parent node.

[ldelossa]

This can be done, but in "litee.nvim". moving the issue there.

[ldelossa]

Currently, nodes do not keep a reference to their parent. If they did, this would become trivial.

[ldelossa]

Right now ever tree has a "depth_table", this is a table that looks like this:

{
0 = { root }
1 = { child1, child2, child3 }
2 = {child4, child5, child6 }
etc...
}

An immediately solution would be to grab the depth_table from the tree to find the parent node.