Update markup_style config.

Updates markup_style config

custom_elements.install

@@ -29,6 +29,6 @@ function custom_elements_update_8201() {
 function custom_elements_update_8202() {
   \Drupal::configFactory()
     ->getEditable('custom_elements.settings')
-    ->setData(['markup_style' => 'web_components'])
+    ->setData(['markup_style' => 'web_component'])
     ->save();
 }