Cleanup warnings

Author: ImMorpheus

src/main/java/org/spongepowered/api/entity/display/DisplayEntity.java

@@ -41,6 +41,7 @@ public interface DisplayEntity extends Entity {
      *
      * @return the transform
      */
+    @Override
     default Transform transform() {
         return this.require(Keys.TRANSFORM);
     }

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

@@ -60,6 +60,7 @@ public interface DamageType extends DefaultedRegistryValue, Nameable, Taggable<D
      * @param tag The tag to check.
      * @return true if this damage type matches the damage type tag.
      */
+    @Override
     boolean is(Tag<DamageType> tag);
 
     /**

src/main/java/org/spongepowered/api/registry/RegistryTypes.java

@@ -506,10 +506,6 @@ public final class RegistryTypes {
 
     // @formatter:on
 
-    private static <V> RegistryType<V> minecraftKey(final String key) {
-        return RegistryType.of(RegistryRoots.MINECRAFT, ResourceKey.minecraft(Objects.requireNonNull(key, "key")));
-    }
-
     private static <V> DefaultedRegistryType<V> minecraftKeyInGame(final String key) {
         return RegistryType.of(RegistryRoots.MINECRAFT, ResourceKey.minecraft(Objects.requireNonNull(key, "key"))).asDefaultedType(Sponge::game);
     }