Heads up: New WITNESS output

Hi Folks,

As a heads-up, I just committed a change to the WITNESS output. It will now
print more detailed information when a lock ordering was established
through a chain of locks (e.g. lock1 is locked before lock2, lock2 is
locked before lock3; therefore, locking lock3 before lock1 is a LOR).

An example of the new output is in the review request (
https://reviews.freebsd.org/D54785).

If you want to restore the old behavior, you can set
the debug.witness.trace sysctl/tunable to 1.

In the meantime, please let me know if you run into any trouble with the
new functionality.

Jonathan