Use SGML entities more consistently.

This also makes more of these files 7bit clean. The Big5, KOI-8 and
eucJP encoded files are already doing without these super ugly SGML
entities, the "latin" languages still need better toolchain support
before we can convert them all to proper UTF-8.
Spelling fixes for sys/amd64
Spelling fixes for sys/arm
Spelling fixes for sys/boot
Spelling fixes for sys/cam
Spelling fixes for sys/cddl
Spelling fixes for sys/compat
Spelling fixes for sys/contrib/altq
Spelling fixes for sys/arm
Spelling fixes for sys/cam
Spelling fixes for sys/dev
Spelling fixes for sys/boot
Spelling fixes for sys/compat
Spelling fixes for sys/crypto
Spelling fixes for sys/conf
Spelling fixes for sys/cddl