abbreviated textual email formatter (patch included)

Attached is a very simple patch to add a very simple email formatter. It takes an email address, "user.name@subdomain.example.com" and abbreviates it as the simple text "user.name@subdomain" with no link. This is perhaps not useful for everyone, but is very handy for people who have a semantically-relevant subdomain and where users can figure out the address from the abbreviated form easily.