Customize Bouncer Messages

I have registration disabled right now and want to add some text to the bouncer message. Looking through the documentation I can see there is a pluggable function to render errors (https://github.com/miled/wordpress-social-login/search?q=wsl_render_error_page) and have seen where the errors are rendered in wsl.error.pages.php inside the notice-message div. How can I add code to the wsl.error.pages.php and maintain the ability to update the plugin in the future?