Tag irssi entry with assigned CVEs, while here wrap at 80 and reference PR

PR: 215800
Security: CVE-2017-5193
Security: CVE-2017-5194
Security: CVE-2017-5195
Security: CVE-2017-5196
Security: https://vuxml.FreeBSD.org/freebsd/3d6be69b-d365-11e6-a071-001e67f15f5a.html