add missing override annotation

src/magic/model/MagicCardDefinition.java

@@ -259,6 +259,7 @@ public class MagicCardDefinition implements MagicAbilityStore, IRenderableCard {
         return valid;
     }
 
+    @Override
     public boolean isInvalid() {
         return !valid;
     }

src/magic/model/MagicPermanent.java

@@ -170,6 +170,7 @@ public class MagicPermanent extends MagicObjectImpl implements MagicSource, Magi
         return getController().controlsPermanent(this);
     }
 
+    @Override
     public boolean isInvalid() {
         return !isValid();
     }