Gen3: Impl type effectiveness in two stages (#676)

This avoids any issues arising from lack of truncation in certain cases

Brings implementation inline with Gen1 & 4

Fixes: #675

calc/src/mechanics/gen3.ts

@@ -159,7 +159,8 @@ export function calculateADV(
 
   baseDamage = calculateFinalModsADV(baseDamage, attacker, move, field, desc, isCritical);
 
-  baseDamage = Math.floor(baseDamage * typeEffectiveness);
+  baseDamage = Math.floor(baseDamage * type1Effectiveness);
+  baseDamage = Math.floor(baseDamage * type2Effectiveness);
   result.damage = [];
   for (let i = 85; i <= 100; i++) {
     result.damage[i - 85] = Math.max(1, Math.floor((baseDamage * i) / 100));
@@ -187,7 +188,8 @@ export function calculateADV(
         Math.floor((Math.floor((2 * lv) / 5 + 2) * newAt * newBp) / df) / 50
       );
       newBaseDmg = calculateFinalModsADV(newBaseDmg, attacker, move, field, desc, isCritical);
-      newBaseDmg = Math.floor(newBaseDmg * typeEffectiveness);
+      newBaseDmg = Math.floor(baseDamage * type1Effectiveness);
+      newBaseDmg = Math.floor(baseDamage * type2Effectiveness);
 
       let damageMultiplier = 85;
       result.damage = result.damage.map(affectedAmount => {