Deleting current worktree messes things up

[TamaMcGlinn]

When deleting the current worktree, we end up with still the buffer open inside that worktree, the :pwd becomes E187: Unknown, and we are unable to use Switch_Worktree because of E344: Can't find directory "/home/...the_deleted_worktree".

Sidenote: Harpoon also throws lots of errors, making it really impossible to do anything but shutdown and restart neovim.

A good solution could be to first open the parent dir of the worktree we just deleted.