Issue #3420400 - Add help hook

Closes #3420400

image_hover_effects.module

@@ -5,8 +5,23 @@
  * Primary module hooks for Image Hover Effects module.
  */
 
+use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Template\Attribute;
 
+/**
+ * Implements hook_help().
+ */
+function image_hover_effects_help($route_name, RouteMatchInterface $route_match) {
+  switch ($route_name) {
+    case 'help.page.image_hover_effects':
+      $output = '';
+      $output .= '<h3>' . t('About') . '</h3>';
+      $output .= '<p>' . t('Provides private entity fields functionality.') . '</p>';
+      $output .= '<p>' . t('The hover effect option is added to the field formatter of the core Image field. Since it only makes sense to have a hover effect on an image that is a link, the styling depends on a link being wrapped around the image.') . '</p>';
+      return $output;
+  }
+}
+
 /**
  * Implements hook_theme().
  */