help_topics.module

<?php


/**
 * @file
 * Displays help topics provided by modules and themes.
 */
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Url;

/**
 * Implements hook_help().
 */
function help_topics_help($route_name, RouteMatchInterface $route_match) {
    if ($route_name == 'help.page.help_topics') {
        $help_home = Url::fromRoute('help.main')->toString();
        $output = '<h2>' . t('About') . '</h2>';
        $output .= '<p>' . t('The Help Topics module has been moved to the Help module.') . '</p>';
        $output .= '<p>' . t('See the <a href=":help_page">Help page</a> to view topics.', [
            ':help_page' => $help_home,
        ]) . '</p>';
        return [
            '#markup' => $output,
        ];
    }
}