Carrying the Master Key of Thievery in open inventory improves thievery chances.

The MKoT has to meet is_roguish_key() criteria, meaning it has to at
least be uncursed for Rogues, and blessed for all others.

Author: k21971

doc/evilhack-changelog.md

@@ -3362,4 +3362,6 @@ The following changes to date are:
   and the object placed inside of it that made the bag blow up
 - Fix: Tiamat couldn't fly
 - Fix: disarming spear trap chances luck check was inverted
+- Carrying the Master Key of Thievery in open inventory improves thievery
+  chances
 

src/uhitm.c

@@ -2541,6 +2541,8 @@ struct attack *mattk;
 
     /* other conditions that could affect success, and these
        can stack if multiple conditions are met */
+    if (has_roguish_key(&youmonst))
+        other -= 6; /* MKoT in open inventory, meets is_roguish_key() criteria */
     if (mdef->mfrozen) /* target is immobile or incapacitated */
         other -= 5;
     if (mdef->mconf || mdef->mstun) /* target can't think straight */