Reduce the effect of luck on to-hit

Luck has a massive effect on the to-hit chance; maximum luck alone
(which almost everyone has past the midpoint of the game) gives
10 points to to-hit, so accounts for 50% chance alone, excluding all
other effects.

Multiple variants do something similar to this, so it is well tested.
This version comes from xNetHack by copperwater <aosdict@gmail.com>,
and allows the +1 or -1 luck adjustments of early game, such as full moon,
to have an effect.

doc/fixes3-7-0.txt

@@ -1558,6 +1558,7 @@ winter wolf cub was missing for monster to lycanthrope conversion
 monster elves shooting arrows weren't getting intended small to-hit and damage
 	bonuses
 safe armor enchantment limit is lowered by one for magical armor
+luck has a reduced effect on to-hit chance
 
 
 Fixes to 3.7.0-x General Problems Exposed Via git Repository

src/uhitm.c

@@ -372,7 +372,8 @@ find_roll_to_hit(
 
     *role_roll_penalty = 0; /* default is `none' */
 
-    tmp = 1 + Luck + abon() + find_mac(mtmp) + u.uhitinc
+    tmp = 1 + abon() + find_mac(mtmp) + u.uhitinc
+          + (sgn(Luck) * ((abs(Luck) + 2) / 3))
           + maybe_polyd(gy.youmonst.data->mlevel, u.ulevel);
 
     /* some actions should occur only once during multiple attacks */