Quell Waiting for your editor to close the file... hint

[blairconrad]

When the tests run, git rebase prints some hints to the console.
The exact placement varies (since the tests are run concurrently),
but looks something like

test stack::tests::test_stack_stops_at_merges ... ok
hint: Waiting for your editor to close the file... hint: Waiting for your editor to close the file... test tests::foreign_author_with_force_author_config ... ok
test tests::foreign_author_with_force_author_flag ... ok

Remove the hints by configuring each new git repo.