replace groovy code with ability in card script

release/Magarena/scripts/Mnemonic_Wall.groovy

@@ -1,29 +0,0 @@
-[
-    new MagicWhenComesIntoPlayTrigger() {
-        @Override
-        public MagicEvent executeTrigger(final MagicGame game,final MagicPermanent permanent, final MagicPayedCost payedCost) {
-            return new MagicEvent(
-                permanent,
-                new MagicMayChoice(
-                    MagicTargetChoice.TARGET_INSTANT_OR_SORCERY_CARD_FROM_GRAVEYARD
-                ),
-                MagicGraveyardTargetPicker.ReturnToHand,
-                this,
-                "PN may\$ return target instant or sorcery card\$ " +
-                "from his or her graveyard to his or her hand."
-            );
-        }
-
-        @Override
-        public void executeEvent(final MagicGame game, final MagicEvent event) {
-            if (event.isYes()) {
-                event.processTargetCard(game,new MagicCardAction() {
-                    public void doAction(final MagicCard card) {
-                        game.doAction(new MagicRemoveCardAction(card,MagicLocationType.Graveyard));
-                        game.doAction(new MagicMoveCardAction(card,MagicLocationType.Graveyard,MagicLocationType.OwnersHand));
-                    }
-                });
-            }
-        }
-    }
-]

release/Magarena/scripts/Mnemonic_Wall.txt

@@ -7,6 +7,6 @@ type=Creature
 subtype=Wall
 cost={4}{U}
 pt=0/4
-ability=defender
+ability=defender;\
+        enters effect PN may return target instant or sorcery card from your graveyard to your hand.
 timing=main
-requires_groovy_code