add: depricated attribute to RPS Rank Response

Author: nebocco

atcoder-problems-backend/src/server/ranking/rated_point_sum.rs

@@ -9,7 +9,7 @@ use async_trait::async_trait;
 use serde::Serialize;
 use sql_client::rated_point_sum::RatedPointSumClient;
 
-// will be deprecated and replaced with super::RankingResponse
+#[deprecated(note = "this special Response type will be deprecated and replaced with super::RankingResponse")]
 #[derive(Debug, Serialize)]
 pub(crate) struct RPSRankingResponse {
     user_id: String,