Final touches to 11.2-RELEASE release notes:

• Remove an empty section that was left over from a previous commit to prune empty sections.
• Add a note about a late discovered issue with zfsd(8) (Bugzilla 228750). Fix a sentence stop while here.
• Document SA-18:07, which had been included in RC3.
• Fix FreeBSD versions in the installation.html page.

Approved by: re (implicit, relnotes)
Sponsored by: The FreeBSD Foundation