updated core to 8.6.1 via composer

core/modules/help/src/Controller/HelpController.php

@@ -107,7 +107,8 @@ class HelpController extends ControllerBase {
    *   A module name to display a help page for.
    *
    * @return array
-   *   A render array as expected by drupal_render().
+   *   A render array as expected by
+   *   \Drupal\Core\Render\RendererInterface::render().
    *
    * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
    */
@@ -119,7 +120,7 @@ class HelpController extends ControllerBase {
 
       $info = system_get_info('module', $name);
       if ($info['package'] === 'Core (Experimental)') {
-        drupal_set_message($this->t('This module is experimental. <a href=":url">Experimental modules</a> are provided for testing purposes only. Use at your own risk.', [':url' => 'https://www.drupal.org/core/experimental']), 'warning');
+        $this->messenger()->addWarning($this->t('This module is experimental. <a href=":url">Experimental modules</a> are provided for testing purposes only. Use at your own risk.', [':url' => 'https://www.drupal.org/core/experimental']));
       }
 
       $temp = $this->moduleHandler()->invoke($name, 'help', ["help.page.$name", $this->routeMatch]);

core/modules/help/src/HelpSectionPluginInterface.php

@@ -17,7 +17,6 @@ use Drupal\Core\Cache\CacheableDependencyInterface;
  */
 interface HelpSectionPluginInterface extends PluginInspectionInterface, CacheableDependencyInterface {
 
-
   /**
    * Returns the title of the help section.
    *