man filesystems: move driver pages to section four

Filesystem manual pages describe drivers, not formats;
except for fs, which describes the structures of ffs/ufs,
not how to use it in the system.

man filesystems: move driver pages to section four

Filesystem manual pages describe drivers, not formats;
except for fs, which describes the structures of ffs/ufs,
not how to use it in the system.

Reported by: emaste
Reviewed by: des, imp, meena (previous version)
Pull Request: https://github.com/freebsd/freebsd-src/pull/1077

show more ...