Continue updating/refactoring classes

Most code is matched from `Grasscutter-Quests`.

src/main/java/emu/grasscutter/server/event/entity/EntityDamageEvent.java

@@ -1,30 +1,24 @@
-package emu.grasscutter.server.event.entity;
-
-import emu.grasscutter.game.entity.GameEntity;
-import emu.grasscutter.server.event.Cancellable;
-import emu.grasscutter.server.event.types.EntityEvent;
-import javax.annotation.Nullable;
-
-public final class EntityDamageEvent extends EntityEvent implements Cancellable {
-    @Nullable private final GameEntity damager;
-    private float damage;
-
-    public EntityDamageEvent(GameEntity entity, float damage, @Nullable GameEntity damager) {
-        super(entity);
-
-        this.damage = damage;
-        this.damager = damager;
-    }
-
-    public float getDamage() {
-        return this.damage;
-    }
-
-    public void setDamage(float damage) {
-        this.damage = damage;
-    }
-
-    @Nullable public GameEntity getDamager() {
-        return this.damager;
-    }
-}
+package emu.grasscutter.server.event.entity;
+
+import emu.grasscutter.game.entity.GameEntity;
+import emu.grasscutter.game.props.ElementType;
+import emu.grasscutter.server.event.Cancellable;
+import emu.grasscutter.server.event.types.EntityEvent;
+import lombok.Getter;
+import lombok.Setter;
+
+import javax.annotation.Nullable;
+
+public final class EntityDamageEvent extends EntityEvent implements Cancellable {
+    @Getter @Setter private float damage;
+    @Getter @Setter private ElementType attackElementType;
+    @Getter @Nullable private final GameEntity damager;
+
+    public EntityDamageEvent(GameEntity entity, float damage, ElementType attackElementType, @Nullable GameEntity damager) {
+        super(entity);
+
+        this.damage = damage;
+        this.attackElementType = attackElementType;
+        this.damager = damager;
+    }
+}