fix comment

bridge-history-api/internal/controller/fetcher/l2_fetcher.go

@@ -120,8 +120,8 @@ func (c *L2MessageFetcher) updateL2WithdrawMessageProofs(ctx context.Context, l2
 	}
 
 	for i, messageHash := range messageHashes {
-		// AppendMessages is called for each message individually to obtain the correct proofs
-		// for the state of the trie after each message is appended.
+		// AppendMessages returns the proofs for the entire tree after all messages have been inserted,
+		// so it is called for each message individually to obtain the correct proofs.
 		proof := withdrawTrie.AppendMessages([]common.Hash{messageHash})
 		if err != nil {
 			log.Error("error generating proof", "messageHash", messageHash, "error", err)