Update DamageStepType.java

Author: MrHell228

src/main/java/org/spongepowered/api/event/cause/entity/damage/DamageStepType.java

@@ -32,7 +32,7 @@
  * Represents a type of {@link DamageStep}.
  */
 @CatalogedBy(DamageStepTypes.class)
-public interface DamageStepType extends DefaultedRegistryValue {
+public interface DamageStepType extends DefaultedRegistryValue<DamageStepType> {
 
     /**
      * Creates a new {@link DamageStepType}.