adds attr

Content.Shared/Interfaces/GameObjects/Components/Interaction/IEquippedHand.cs

@@ -2,6 +2,7 @@
 using Content.Shared.GameObjects.Components.Inventory;
 using Content.Shared.GameObjects.Components.Items;
 using JetBrains.Annotations;
+using Robust.Shared;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Interfaces.GameObjects;
 
@@ -13,6 +14,7 @@ namespace Content.Shared.Interfaces.GameObjects.Components
     ///     This includes moving the entity from a non-hand slot into a hand slot
     ///     (which would also fire <see cref="IUnequipped"/>).
     /// </summary>
+    [RequiresExplicitImplementation]
     public interface IEquippedHand
     {
         void EquippedHand(EquippedHandEventArgs eventArgs);