Hello.

I've added support for hostname completion in eshell when using ssh and
scp. It gathers a list of hostnames from the ~/.ssh/known_hosts file.

SSH completion completes only from the list of hostnames; SCP completes
from files and directories currently present plus the list of
hostnames. It also assumes that each hostname is followed by either a
space or a comma, which is the case on the systems I've checked but may
not be a universal rule.

Would this be suitable for inclusion in Emacs? It may not be portable to
all the systems Emacs supports since it assumes the existence of the
known_hosts file, but I think it's fairly useful nonetheless.

I've attached the file; please comment.

-Phil