docs: clean up (#113)

Signed-off-by: Jingfu Wang <jingfu.wang@coinbase.com>

client/client.go

@@ -814,7 +814,8 @@ func (ec *SDKClient) GetErc20TransferGasLimit(
 		return 0, fmt.Errorf("unable to find contract info for currency %s", currency.Symbol)
 	}
 
-	// ToAddress for erc20 transfers is the contract address
+	// toAddress in function param is the address to receive token
+	// the To address in EstimateGas is the contract address
 	contractAddress := common.HexToAddress(contract.(string))
 	data := GenerateErc20TransferData(toAddress, value)
 	gasLimit, err := ec.EstimateGas(ctx, ethereum.CallMsg{

services/construction/metadata.go

@@ -72,6 +72,7 @@ func (s APIService) ConstructionMetadata( //nolint
 		return nil, sdkTypes.WrapErr(sdkTypes.ErrGasPriceError, err)
 	}
 
+	// Calculate contract data for contract call
 	if len(input.ContractAddress) > 0 && len(input.ContractData) == 0 {
 		contractData, err := ConstructContractCallDataGeneric(input.MethodSignature, input.MethodArgs)
 		if err != nil {