linking.
* Fix disorder in the SEE ALSO sections of aio_*(2).
* Remove unnecessary cross-references from the SEE ALSO sections of
aio_*(2); config(8), kldload(8) and kldunload(8) are cross-referenced
from aio(4).
* Remove the KERNEL OPTIONS sections from aio_*(2), now that these
pages cross-reference aio(4), which contains suitable kernel linking
reference material.