fix #K3925 - u.ustuck of long worm tail

Don't allow stick/wrap/engulf attacks directed at long worm tails
to succeed.  Achieved by making sure that 'notonhead' is up do date
in a bunch of places and utilizing the fairly recent can't-{stick,wrap,
engulf}-unsolid-monsters code.

Should prevent a 'sanity_check' warning about being too far from
u.ustuck that would happen when holding the tail while the head was
not adjacent to the hero.

Also don't let pet ranged attacks from choosing a long worm's tail
as target.  They'll still be able to target long worms provided that
the head is lined up and not shielded by tail segment(s).

doc/fixes3-7-0.txt

@@ -1145,7 +1145,7 @@ give feedback if monster holding onto the hero has to let go when hero polys
 	into a form which can't be held
 prevent hug attacks and touch or engulf attacks for wrap, stick-to, and
 	digestion damage from succeeding against unsolid targets (ghosts,
-	vortices, a few others)
+	vortices, a few others) or against worm tails
 wand of speed gives temporary speed, potion gives intrinsic
 some monsters (riders, shopkeepers, priests, quest leader) can break boulders
 corpse-eating monsters will go out of their way to eat corpses on the floor