Resolve #3451642 "Improve linkit attributes"

schemadotorg.schemadotorg.inc

@@ -195,8 +195,10 @@ function linkit_schemadotorg_property_field_alter(
     return;
   }
 
-  // Use linkit for the link URL autocompletion.
-  $widget_id = 'linkit';
+  // Use Linkit or Linkit (with attributes) for the link URL autocompletion.
+  $widget_id = (\Drupal::moduleHandler()->moduleExists('linkit_attributes'))
+    ? 'linkit_attributes'
+    : 'linkit';
   $widget_settings = ['linkit_auto_link_text' => TRUE];
 }