Update anti-aliased fonts section. Patch supplied by Tim Moore
<timmoore88_gmail.com>, based on bug report by Brandon S Allbery
<allbery.b@gmail.com>. Other edits added to fix wording in old section
and correct indentation in programlisting elements (content, in this
case).

PR: 193612
Submitted by: Brandon S Allbery <allbery.b@gmail.com>
Sponsored by: iXsystems
Differential Revision: https://reviews.freebsd.org/D7841