doc: Remove outdated scriptChange TODO comment

src/wallet/spend.cpp

@@ -665,8 +665,6 @@ static bool CreateTransactionInternal(
     }
 
     // Create change script that will be used if we need change
-    // TODO: pass in scriptChange instead of reservedest so
-    // change transaction isn't always pay-to-bitcoin-address
     CScript scriptChange;
 
     // coin control: send change to custom address