Use consistent field ordering

Clippy emits:

  warning: struct constructor field order is inconsistent with struct
  definition field order

As suggested, re-order the fields to be consistent with the struct
definition.

src/wallet/coin_selection.rs

@@ -255,8 +255,8 @@ impl OutputGroup {
         let effective_value = weighted_utxo.utxo.txout().value as i64 - fee.ceil() as i64;
         OutputGroup {
             weighted_utxo,
-            effective_value,
             fee,
+            effective_value,
         }
     }
 }