Release notes documentation:

Release notes documentation:
- r346296, clang (and friends) 8.0.0.
- r346981, WPA 2.8.
- r348343, OpenSSL 1.0.2s.
- r348607, libarchive(3) updates.
- r348980, OpenPAM updates.
- r346855, cxgbe(4) hash filters, NAT offloading, SMAC/DMAC
           swapping filtering.
- r346940, cxgbe(4) T4/5/6 firmware update.
- r348588, geli(8) weak algorithm deprecation warnings.
- r346690, ZFS parallel mounting.
- r348753, deprecation warnings enabled.
- r346212, NAT64 CLAT support.

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