Fix typos in error type `Display` messages

zcash_client_backend/src/fees.rs

@@ -105,7 +105,7 @@ impl<CE: fmt::Display, N: fmt::Display> fmt::Display for ChangeError<CE, N> {
                 required,
             } => write!(
                 f,
-                "Insufficient funds: required {} ZAT, but only {} ZAT were available.",
+                "Insufficient funds: required {} zatoshis, but only {} zatoshis were available.",
                 i64::from(required),
                 i64::from(available)
             ),

zcash_primitives/src/transaction/components/amount.rs

@@ -265,7 +265,10 @@ impl std::fmt::Display for BalanceError {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match &self {
             BalanceError::Overflow => {
-                write!(f, "Amount addition resulted in a value the valid range.")
+                write!(
+                    f,
+                    "Amount addition resulted in a value outside the valid range."
+                )
             }
             BalanceError::Underflow => write!(
                 f,