Fix doxygen comment for payTxFee

src/wallet/wallet.cpp

@@ -37,9 +37,7 @@
 using namespace std;
 using namespace libzcash;
 
-/**
- * Settings
- */
+/** Transaction fee set by the user */
 CFeeRate payTxFee(DEFAULT_TRANSACTION_FEE);
 unsigned int nTxConfirmTarget = DEFAULT_TX_CONFIRM_TARGET;
 bool bSpendZeroConfChange = DEFAULT_SPEND_ZEROCONF_CHANGE;