feat(asakatsu-bot): add notification message when no reactions are found

Author: tknkaa

bots/asakatsu-bot/commands/check.ts

@@ -25,6 +25,7 @@ await execWithContext(async (ctx) => {
   const users = await reaction.users.fetch();
   const targets = users.filter((u) => !u.bot).map((u) => u.id);
   if (!targets.length) {
+    await ctx.channel.send("リアクションないの悲しいって")
     console.log("OK: ユーザーのリアクション無し");
     return;
   }