Re: git rebase --interactive squash/squish/fold/rollup

I wonder if a better approach might be to add an operator to squash
rather than another verb. "squash!" maybe? This has the nice property
that future verbs that have both interactive and non-interactive modes
could be made consistent with squash easily, rather than having to think
of another synonym.

We could also have   edit!  to just straight the commit message stage,
and then automatically continue.