fix: custom weapons not doing default damage when set to below 0 (#518)

* fix custom weapons not doing default damage when set to below 0

* make default damage -1

Author: TtroubleTT

EXILED/Exiled.CustomItems/API/Features/CustomWeapon.cs

@@ -52,7 +52,7 @@ public override ItemType Type
         /// <summary>
         /// Gets or sets the weapon damage.
         /// </summary>
-        public virtual float Damage { get; set; } = float.NaN;
+        public virtual float Damage { get; set; } = -1;
 
         /// <summary>
         /// Gets or sets a value indicating how big of a clip the weapon will have.
@@ -205,7 +205,7 @@ protected virtual void OnShot(ShotEventArgs ev)
         /// <param name="ev"><see cref="HurtingEventArgs"/>.</param>
         protected virtual void OnHurting(HurtingEventArgs ev)
         {
-            if (ev.IsAllowed && Damage != float.NaN)
+            if (ev.IsAllowed && Damage >= 0)
                 ev.Amount = Damage;
         }