Fix date.

document usbnet diagnostics in usbnet(4). remove all the no longer
present messages in specific drivers for the usbnet drivers.

branches: 1.7.64;
Convert TNF licenses to new 2 clause variant

branches: 1.6.34; 1.6.36;
Edit -mdoc usage.

* There is no -indent option to .Bd or .Bl, although you would
never know that from its frequent use in this tree. There is a
"-offset indent" combination that makes sense, and you can certainly
say "-width indent".

* Also, you can't markup the -width option argument, tho you CAN
use a callable macro. So "-width Ar filename" doesn't make sense,
but either "-width Ar" or "-width filename" does, as might something
like "-width xxfilename" for a little extra space.

* There are a lot of needlessly complex hanging tag macros in man4 used
to create simple item lists. Those should be simplified one of these
days before someone copies and edits yet another man4 page.

Fix paragraph problems, sort sections, sort Xrefs in SEE ALSO, and other
miscellaneous fixes.

upl(4) is a IPv4 only device.

Add a couple of Inland adapters I forgot last time.

Add PC Linq to the list of hardware.

Add upl(4) man page.