fix B16006 - cancelled monster-monster attacks

fix B16006 - cancelled monster-monster attacks

     Various damage types which wouldn't work when a cancelled monster
attacks the player were working when it attacked other monsters instead.
Besides attempting to fix that, this also makes cloaks and other magic
blocking armor ("magic cancellation factor") work for monsters similar
to the way it works for the player.

     Most types of damage appear to revert to physical damage when the
attacker is cancelled; I'm not sure that's appropriate in many of the
instances.  The leg-pricking case was clearly wrong, since it gives
messages about the attack failing yet still hurt the character.

     This really needs a lot more testing than I have energy for.  I've
tried to clean up various inconsistencies and may have made some typos
in the process.