Core/DB: Misc fixes

Source/Game/Entities/Unit/Unit.Fields.cs

@@ -132,9 +132,8 @@ namespace Game.Entities
         ushort _meleeAnimKitId;
     }
 
-    public class DiminishingReturn
+    public struct DiminishingReturn
     {
-        public DiminishingReturn() { }
         public DiminishingReturn(uint hitTime, DiminishingLevels hitCount)
         {
             Stack = 0;

Source/Game/Entities/Unit/Unit.Spells.cs

@@ -2649,9 +2649,6 @@ namespace Game.Entities
         public DiminishingLevels GetDiminishing(DiminishingGroup group)
         {
             DiminishingReturn diminish = m_Diminishing[(int)group];
-            if (diminish == null)
-                return DiminishingLevels.Level1;
-
             if (diminish.HitCount == 0)
                 return DiminishingLevels.Level1;
 
@@ -2778,8 +2775,6 @@ namespace Game.Entities
         {
             // Checking for existing in the table
             DiminishingReturn diminish = m_Diminishing[(int)group];
-            if (diminish == null)
-                diminish = new DiminishingReturn();
 
             if (apply)
                 ++diminish.Stack;