Parent field entity in plugin interface

I don't think this was being done before, but might have missed it.

I've made a few settings plugins for my own use cases, things like 'sticky to top' and 'hide exposed form' etc, having the plugin interface is really good.

I found adding the parent field to the view very handy. From there you can get parent entity, which in my case is a paragraph, and therefore all the other sibling fields. This data/context can be useful.

I added :

'field' => $item,

to

      $view->element['#viewsreference'] = [
        'field' => $item,
        'data' => $data,
        'enabled_settings' => array_filter($this->getFieldSetting('enabled_settings')),
      ];

in viewsreference/src/Plugin/Field/FieldFormatter/ViewsReferenceFieldFormatter.php

This allows me to access the parent field and entity in my plugin's alterView function using :

 $parent = $view->element['#viewsreference']['field']->getEntity();

I've attached a patch that I'm applying to the "2.x-dev" version in composer.

Might be useful to someone else.