message: [lang] Use default trait
diff: @@ -121,8 +121,7 @@ fn codegen_for_instantiate(tokens: &mut TokenStream2, contract: &hir::Contract)
  );
  let msg_fn_args = {
  - let mut msg_fn_args: Punctuated<ast::FnArg, Token![,]> =
  - Punctuated::new();
  + let mut msg_fn_args: Punctuated<ast::FnArg, Token![,]> = Default::default();
  for input in message.sig.decl.inputs.iter().skip(1) {
  msg_fn_args.push(input.clone())
  }
  @@ -130,8 +129,7 @@ fn codegen_for_instantiate(tokens: &mut TokenStream2, contract: &hir::Contract)
  };
  let msg_call_args = {
  - let mut msg_call_args: Punctuated<syn::Pat, Token![,]> =
  - Punctuated::new();
  + let mut msg_call_args: Punctuated<syn::Pat, Token![,]> = Default::default();
  for captured in msg_fn_args.iter().filter_map(|fn_arg| {
  if let ast::FnArg::Captured(captured) = fn_arg {
  Some(captured)
  