doc: include wtxid in TransactionDescriptionString

src/wallet/rpc/transactions.cpp

@@ -432,6 +432,7 @@ static const std::vector<RPCResult> TransactionDescriptionString()
            {RPCResult::Type::NUM, "blockindex", /*optional=*/true, "The index of the transaction in the block that includes it."},
            {RPCResult::Type::NUM_TIME, "blocktime", /*optional=*/true, "The block time expressed in " + UNIX_EPOCH_TIME + "."},
            {RPCResult::Type::STR_HEX, "txid", "The transaction id."},
+           {RPCResult::Type::STR_HEX, "wtxid", "The hash of serialized transaction, including witness data."},
            {RPCResult::Type::ARR, "walletconflicts", "Conflicting transaction ids.",
            {
                {RPCResult::Type::STR_HEX, "txid", "The transaction id."},