Add sysctl documentation strings. The descriptions are derived from tuning(7). One of the descriptions references tuning(7) because it is too complex to adequatly describe here (it is not a simple boolean sysctl) and users should be warned to that.
Add sysctl documentation strings. The descriptions are derived
from tuning(7). One of the descriptions references tuning(7) because
it is too complex to adequatly describe here (it is not a simple
boolean sysctl) and users should be warned to that.

Reviewed by:	alc, kib
Approved by:	gnn (mentor)

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase