[minor] add title to /username.keys
It is easy to get ssh keys from gitlab and give access to machines, but lack of title in the exported key makes it harder to recognize the key.
For example if I was to give user pravi access to a server, I download gitlab.com/pravi.keys and add it to .ssh/authorized_keys. But when I have many keys there, lack of title in the keys make it harder to recognize.