Read More Button

Hey,
I’m trying to change the read more button that displays when a product is out of stock(on the shop page). I would like the button to say “Out of stock” instead of “Read more”. I am not finding I should inject to code to do such, more so I don’t know if the code I’m using is adequate.

Code using:
add_filter(‘gettext’, ‘translate_text’);
add_filter(‘ngettext’, ‘translate_text’);

function translate_text($translated) {
$translated = str_ireplace(‘Read More’, ‘Contact Us’, $translated);
return $translated;
}

Thanks,