Command for moving or deleting “done” items

[jotaen]

When an item is done, it could (optionally) be

• just deleted
• or moved to a separate group, e.g.

  Todos
  [ ] Something
  [ ] Some other thing
  
  Done
  [x] Do this
  [x] Do that
  

Both could be somehow configured via the package settings (e.g. for the second option, what the “done” section is called).

Another idea could be to offer some sort of “clean up” command, that does such things on-demand.