Adjust ranged weapons slightly

Buff the hand crossbow & shortbow slightly to account for the
lack of ammo in the early-game (when they'll be used) - +1 base
dam apiece, and +1 base acc for the shortbow to make it 'feel' a
little more satisfying.

Adjust the triple crossbow very slightly downward - turns out the
'armour piercing' effect was more strong than expected, especially
when combining weapon & ammo brands. -1 base dam.

crawl-ref/source/itemprop.cc

@@ -352,17 +352,17 @@ static const weapon_def Weapon_prop[] =
         SK_SLINGS,       SIZE_LITTLE,  SIZE_SMALL, MI_STONE,
         DAMV_NON_MELEE, 2, 2 },
 
-    { WPN_HAND_CROSSBOW,     "hand crossbow",      11,  5, 15,  50,  5,
+    { WPN_HAND_CROSSBOW,     "hand crossbow",      12,  5, 15,  50,  5,
         SK_CROSSBOWS,    SIZE_LITTLE, SIZE_LITTLE, MI_BOLT,
         DAMV_NON_MELEE, 7, 10 },
     { WPN_ARBALEST,          "arbalest",           18,  2, 19, 150,  8,
         SK_CROSSBOWS,    SIZE_LITTLE, NUM_SIZE_LEVELS, MI_BOLT,
         DAMV_NON_MELEE, 5, 10 },
-    { WPN_TRIPLE_CROSSBOW,   "triple crossbow",    23,  0, 23, 250,  9,
+    { WPN_TRIPLE_CROSSBOW,   "triple crossbow",    22,  0, 23, 250,  9,
         SK_CROSSBOWS,    SIZE_SMALL,  NUM_SIZE_LEVELS, MI_BOLT,
         DAMV_NON_MELEE, 0, 2 },
 
-    { WPN_SHORTBOW,          "shortbow",            8,  1, 13,  90,  2,
+    { WPN_SHORTBOW,          "shortbow",            9,  2, 13,  90,  2,
         SK_BOWS,         SIZE_LITTLE,  NUM_SIZE_LEVELS, MI_ARROW,
         DAMV_NON_MELEE, 8, 10 },
     { WPN_LONGBOW,           "longbow",            15,  0, 17, 120,  3,