add comment for rate limit

proto/centauri/ratelimit/v1beta1/tx.proto

@@ -20,20 +20,26 @@ message MsgAddRateLimit {
   // authority is the address that controls the module (defaults to x/gov unless
   // overwritten).
   string authority = 1 [ (gogoproto.moretags) = "yaml:\"authority\"" ];
+  // denom of the token that is limited
   string denom = 2;
+  // The channel that is limited when transferr ICS 20 packet of denom
   string channel_id = 3;
+  // Max rate limit send
   string max_percent_send = 4 [
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Int",
     (gogoproto.nullable) = false
   ];
+  // Max rate limit receive
   string max_percent_recv = 5 [
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Int",
     (gogoproto.nullable) = false
   ];
+  // Min amount of rate limit (allow transfer max(min-amout, rate-limit))
   string min_rate_limit_amount = 6 [
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Int",
     (gogoproto.nullable) = false
   ];
+  // Duration of rate limit. The rate limit will reset when reach the duration.
   uint64 duration_hours = 7;
 }