feat(wasm-utxo): enhance code readability and multisig iteration

Remove unnecessary blank line in cashaddr module's test section and refactor
multisig script parsing to use iterator methods instead of index-based
loops for better readability and safer iteration.

Issue: BTC-2652

Co-authored-by: llm-git <[email protected]>

Author: OttoAllmendinger

packages/wasm-utxo/src/address/cashaddr.rs

@@ -457,7 +457,6 @@ mod tests {
     ///
     /// Using bech32 crate's `ByteIterExt::bytes_to_fes()` or checksum functions would fail these tests
     /// because they implement Bech32/Bech32m logic, not CashAddr logic.
-
     // Test vector: 20-byte P2PKH payload
     const TEST_HASH_20: &str = "F5BF48B397DAE70BE82B3CCA4793F8EB2B6CDAC9";
 

packages/wasm-utxo/src/fixed_script_wallet/wallet_scripts/checkmultisig.rs

@@ -51,21 +51,21 @@ pub fn parse_multisig_script_2_of_3(script: &ScriptBuf) -> Result<PubTriple, Str
 
     // Extract the three public keys
     let mut keys = Vec::new();
-    for i in 1..4 {
-        match &instructions[i] {
+    for (idx, instruction) in instructions.iter().enumerate().skip(1).take(3) {
+        match instruction {
             Instruction::PushBytes(bytes) => {
                 let key = CompressedPublicKey::from_slice(bytes.as_bytes()).map_err(|e| {
                     format!(
                         "Failed to parse compressed public key at position {}: {}",
-                        i, e
+                        idx, e
                     )
                 })?;
                 keys.push(key);
             }
             _ => {
                 return Err(format!(
                     "Instruction at position {} should be a push bytes instruction",
-                    i
+                    idx
                 ));
             }
         }