style: Relax 80 column rule

Note that the 80 column rule has been relaxed for some time when things
are clearer when a little longer. Add in that things that people grep
for, such as error messages, shouldn't be broken up which is the most
common reason people exceed 80 columns intentionally.

Reviewed by: jhb, domagoj.stolfa@gmail.com
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D30255