Issue #3339168: Implement hook_help()

menu_link_sync.module

@@ -8,7 +8,39 @@ use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Menu\MenuTreeParameters;
 use Drupal\node\Entity\Node;
+use Drupal\Core\Routing\RouteMatchInterface;
 
+/**
+ * Implements hook_help().
+ */
+function menu_link_sync_help($route_name, RouteMatchInterface $route_match) {
+  switch ($route_name) {
+    // Main module help for the menu_link_sync module.
+    case 'help.page.menu_link_sync':
+      $output = '';
+      $output .= '<h3>' . t('About') . '</h3>';
+      $output .= '<p>' . t('The Menu Link Sync module helps synchronize the
+      position of menu items within Drupal installs with separate menus for
+      every language, for instance when we have different "Main Menu -
+      French", "Main Menu - English" and "Main Menu - Spanish" menus.') . '</p>';
+      $output .= '<p>' . t('This synchronization may be useful when the
+      structure of the menus is too different for i18n_menu or Entity
+      Translation to be adequate solutions, but when the trees for
+      different languages are still similar enough for some sort of
+      synchronization of menu structures to be desirable.') . '</p>';
+      $output .= '<p>' . t('This module provides a "Synchronize" button
+      to the "Menu link settings" on the node forms for translated nodes.
+      By pressing the "Synchronize" button, the parent and the relative
+      tree position of the menu link for this translated node are
+      automatically calculated to be as close as possible to the
+      parent and relative position of the menu link for the "source"
+      node. The form will then be updated through an AJAX call and the
+      new parent and weight will be automatically selected.') . '</p>';
+      return $output;
+
+    default:
+  }
+}
 // Integration with menu_link_weight module.
 require_once DRUPAL_ROOT . '/' . \Drupal::service('extension.path.resolver')->getPath('module', 'menu_link_sync') . '/menu_link_sync.menu_link_weight.inc';