We already have :close and :abort, could we simply make the existing
Perhaps somewhat selfishly, I don't really want to remember that :close
works for the message viewer and the terminal, abort for the composer,
and if I want to close one by name I should use :close-tab.
I think it would be possible to just have a single :close command which
uses a type switch to do the additional cleanup required by the term and
the composer, and it could also be extended to take an optional tab
name, acting on the focused tab if none is provided.