In v3 UNIX, the kill utility is documented in category 8, not 1.
Add a note of it.
http://minnie.tuhs.org/cgi-bin/utree.pl?file=V3/man/man8/kill.8

PR: 211786
Approved by: bcr (mentor)
Obtained from: TUHS
Differential Revision: https://reviews.freebsd.org/D8105