Similar to nvim's telescope this makes it easier to find the right tab
in the list.

The preview takes place in the pane where the tab resides.
- on dismiss: We restore all panes.
- on confirm: We restore all panes except the one where the selected tab
resides. For this reason we collect the active item for each pane before
the tabswither starts.

Release Notes:

- Improved tab switcher, it now shows a preview of the selected tab

Co-authored-by: Julia Ryan <juliaryan3.14@gmail.com>