Bad docs in fly ssh issue

!!! WARNING: We’re now prompting you to save an SSH private key and certificate !!!
!!! (the private key in “id_whatever” and the certificate in “”). !!!
!!! These SSH credentials are time-limited and handling them in files is clunky; !!!
!!! consider running an SSH agent and running this command with -agent. Things !!!
!!! should just sort of work like magic if you do. !!!

It should be --agent, not -agent