still more Master Key of Thievery

Make #untrap while carrying the non-cursed (for rogues) or blessed
(for non-rogues) Key work the same as #invoke has been doing (without
regard to its bless/curse state):  when used on trapped door or chest,
that trap will always be found and disarming it will always succeed.

It should work when carried by monsters too:  if they try to open a
trapped door while carrying the Key (must be blessed since they're
not rogues) the trap will be automatically disarmed.  (Caveat:  that
hasn't been adequately tested.)

TODO (maybe...):  change the #invoke property to detect unseen/secret
door detection instead of #untrap.  The latter isn't completely
redundant; it works when the Key is cursed.  But quest artifacts
strongly resist becoming cursed so that isn't a particularly useful
distinction.

Also, trap hints when wielding the Key without gloves didn't notice
adjacent door and chest traps.  Now it does.  And the behavior is
slightly different:  known traps covered by objects or monsters are
treated like unknown traps as far as the hot/cold hints go.

include/artilist.h

@@ -208,6 +208,9 @@ A("The Palantir of Westernesse",        CRYSTAL_BALL,
       PHYS(5, 0), NO_DFNS, NO_CARY, CREATE_AMMO, A_CHAOTIC, PM_RANGER, NON_PM,
       4000L, NO_COLOR),
 
+    /* MKoT has an additional carry property if the Key is not cursed (for
+       rogues) or blessed (for non-rogues):  #untrap of doors and chests
+       will always find any traps and disarming those will always succeed */
     A("The Master Key of Thievery", SKELETON_KEY,
       (SPFX_NOGEN | SPFX_RESTR | SPFX_INTEL | SPFX_SPEAK),
       (SPFX_WARN | SPFX_TCTRL | SPFX_HPHDAM), 0, NO_ATTK, NO_DFNS, NO_CARY,