Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix some Xr references:

- ada(4): ad(4) - removed, ada(4) would be a self-referencing entry
- cd(4): ad(4) -> ada(4)
- da(4): ad(4) -> ada(4)
- DEVICE_PROBE(9): ugen(5) -> ugen(4)
- ed(4): dhclinet(8) -> dhclient(8) (typo)
- lmc(4): Netgraph(4) -> netgraph(4)
- security(7): rc.conf(8) -> rc.conf(5)
- sfxge(4): cpuset(8) -> cpuset(1)
- sbp(4): sysctl(1) -> sysctl(8)
- portindex(5): build(1) -> build(7)
- u3g(4): usbconfig(5) -> usbconfig(8)
- usb_quirk(4): usbconfig(5) -> usbconfig(8)

Found with: textproc/igor
MFC after: 3 days

Add a description about hw.firewire.hold_count.

MFC: after 3 days
PR: kern/93083

Assorted markup, spelling, and grammar fixes.

o grammar fixes
o removed wrong 's usage

MFC after: 5 days

Add description about tagged queuing.

Add reference to CAM.

mdoc(7) police: Scheduled sweep.

Add description about device detaching.

Add description about kldload and security note.

Add some reference.

Rescaning the bus is usually unnecessary.

mdoc(7) police: overhaul.

Approved by: re

Initial import for IEEE1394 OHCI chipdet device driver and SBP-2 (Serial
Bus Protocol 2:SCSI over IEEE1394) support for CAM.