Make it clear that we need the author to provide their full legal name in the commit record

Submitted by Wayne Beaton @wbeaton

Link to original bug (#522672)

Description

The author field must contain a valid full legal name of the contributor as well as a real email address.

The DCO states (in part):

-- I understand and agree that this project and the contribution are public and that a record of the contribution (including all personal information I submit with it, including my signoff) is maintained indefinitely and may be redistributed consistent with this project or the open source license(s) involved.

Further, contributions cannot be accepted anonymously.