- Added handling to not include parent of top-most list range selection
so that it's not also changed while not visually part of the
selection range.
- Fixed issue where list items could be left over after unnesting, due
to empty checks/removals occuring before all child handling.
- Added node sorting, applied to list items during nest operations so
that selection range remains reliable.
Sibling/child items will now remain at the same visual level during
nesting/un-nested, so only the selected item level is visually altered.
Also added new model-based editor content matching system for tests.
Added list nesting support to allow li > ul style nesting which lexical
didn't do by default.
Adds tab handling for inset/outset controls.
Will be a range of edge-case bugs to squash during testing.
