[Groff] groff mailing lists

[Karl Berry]

The bug-groff mailing list was previously accepting mail from anyone,
thus unfortunately passing on plenty of spam.  With Werner's approval,
I've now configured it to hold messages from "strangers", so there may
be a small delay for first-time posters.

Werner was already moderating the groff and groff-commit lists.

Let me know if any questions or problems.

karl