Minor fixes in comments

Author: dmidem

zebra-chain/src/orchard/arbitrary.rs

@@ -128,8 +128,8 @@ impl Arbitrary for Flags {
     fn arbitrary_with(_args: Self::Parameters) -> Self::Strategy {
         (any::<u8>())
             .prop_map(|byte| {
-                // Clear ENABLE_ZSA: it is only valid in V6, but this strategy
-                // is also used for V5 transactions where it causes a deserialization error.
+                // Clear ENABLE_ZSA: it is only allowed in V6, and this generator is
+                // also used for V5 cases where the flag would make deserialization fail.
                 #[cfg(feature = "tx_v6")]
                 let byte = byte & !(Flags::ENABLE_ZSA.bits());
                 Self::from_bits_truncate(byte)

zebra-chain/src/transaction.rs

@@ -1430,7 +1430,7 @@ impl Transaction {
         &self,
         outputs: &HashMap<transparent::OutPoint, transparent::Output>,
     ) -> Result<ValueBalance<NegativeAllowed>, ValueBalanceError> {
-        // TODO: subtruct zip233_amount if zip233 is approved.
+        // TODO: subtract zip233_amount if zip233 is approved.
         self.transparent_value_balance_from_outputs(outputs)?
             + self.sprout_value_balance()?
             + self.sapling_value_balance()