grammar bit: fatal cockatrice corpse theft (trunk only)
From a bug report, stealing a cockatrice corpse
from a monster while polymorphed into a nymph and not wearing any gloves,
the cause of death ended up being "petrified by cockatrice corpse". It would
also have said the same thing if a stack of multiple corpses was involved.
This fixes both cases, and also hypothetical unique monsters with petrifying
touch. (Last bit tested by temporarily adding Medusa to touch_petrifies().)