Translate the checkout page result

Thank you for your plugin!
It works fine ! The translation is ok except for the checkout page result.

In another topic for changing the language of the Checkout result you said :

add_filter(‘asp_stripe_payments_checkout_page_result’, ‘custom_stripe_checkout_output’, 10, 2);

function custom_stripe_checkout_output($output, $post_data)
{
//TODO create/add your customized text in the $output variable

//return the output variable so the plugin can show it
return $output;
}
I am not easy with php…
1 – Can you write an example into your code above:
for that line: Thank you for your payment = Merci pour votre paiement
2 – Where do I put that code ? Which file ?
Here’s an image for the translation in french.

Thank you