MFC r358891, r358894, r359454, r359513, r359550 and r359556
elf(5) Updates:
- start documenting ELF note sections
- Remove extra Sy from table header
- table markup fixes
- add definitions of FreeBSD notes
- minor update to FreeBSD ELF note descriptions
- correct and expand NT_FREEBSD_NOINIT_TAG description
- expand on NT_FREEBSD_FEATURE_CTL bit definitions
Reviewed by: emaste
Approved by: emaste