chore: improve rdm command

src/main/kotlin/cn/rtast/fancybot/util/item/Item.kt

@@ -8,15 +8,16 @@
 package cn.rtast.fancybot.util.item
 
 import cn.rtast.rob.entity.GroupMessage
+import cn.rtast.rob.util.ob.MessageChain
 import cn.rtast.rob.util.ob.OneBotListener
 
 abstract class Item {
     abstract val itemNames: List<String>
     abstract val itemPrice: Double
 
-    protected open suspend fun redeemInGroup(listener: OneBotListener, message: GroupMessage, after: Double) {}
-
-    suspend fun redeemGroup(listener: OneBotListener, message: GroupMessage, after: Double) {
-        this.redeemInGroup(listener, message, after)
-    }
+    abstract suspend fun redeemInGroup(
+        listener: OneBotListener,
+        message: GroupMessage,
+        after: Double
+    ): MessageChain.Builder
 }