intro.5: Import description table from OpenBSD

Looking around at how everyone else is doing it, this list seems nearly
perfect to me and we should just import it from them. I have added "and
streams" because we have some explanations of those in this section too.

PR: 248562
MFC after: 3 days
Obtained from: OpenBSD
Approved by: mhorne (mentor)
Reviewed by: imp, mhorne, Lexi Winter <lexi@le-fay.org>
Pull Request: https://github.com/freebsd/freebsd-src/pull/1534

(cherry picked from commit 26ec376536622e8fec8f40847aa9b2d1121d585d)