Core/AI: Implemented functionality for _isCombatMovementAllowed in ScriptedAI, only when AttackStart is called.

src/server/game/AI/ScriptedAI/ScriptedCreature.h

@@ -136,6 +136,9 @@ struct ScriptedAI : public CreatureAI
     //Called at creature aggro either by MoveInLOS or Attack Start
     void EnterCombat(Unit* /*victim*/) {}
 
+    // Called before EnterCombat even before the creature is in combat.
+    void AttackStart(Unit* /*target*/);
+
     // *************
     //AI Helper Functions
     // *************
@@ -191,7 +194,11 @@ struct ScriptedAI : public CreatureAI
 
     void SetEquipmentSlots(bool loadDefault, int32 mainHand = EQUIP_NO_CHANGE, int32 offHand = EQUIP_NO_CHANGE, int32 ranged = EQUIP_NO_CHANGE);
 
-    //Generally used to control if MoveChase() is to be used or not in AttackStart(). Some creatures does not chase victims
+    // Used to control if MoveChase() is to be used or not in AttackStart(). Some creatures does not chase victims
+    // NOTE: If you use SetCombatMovement while the creature is in combat, it will do NOTHING - This only affects AttackStart
+    //       You should make the necessary to make it happen so.
+    //       Remember that if you modified _isCombatMovementAllowed (e.g: using SetCombatMovement) it will not be reset at Reset().
+    //       It will keep the last value you set.
     void SetCombatMovement(bool allowMovement);
     bool IsCombatMovementAllowed() const { return _isCombatMovementAllowed; }