prune: replace --biject with --pair
People have been complaining about `--biject` being to obscure for a while.
A recent discussion with Pulkit Goyal and Dan Villiom Podlaski Christiansen
produce some new concrete proposal that we liked. We eventually settle on using
`--pair`. The `--biject` flag will be kept as an alias for a while.
#!/bin/sh
sleep 5
echo "new desc" >> $1