documentSelfTokens example

foreach ($previous as $id => $label) {
        $options[$optgroup_fields]["{{ $id }}"] = substr(strrchr($label, ":"), 2);
      }
      // Add the field to the list of options.       $options[$optgroup_fields]["{{ {$this->options['id']} }}"] = substr(strrchr($this->adminLabel(), ":"), 2);

      foreach ($this->view->display_handler->getHandlers('argument') as $arg => $handler) {
        $options[$optgroup_arguments]["{{ arguments.$arg }}"] = $this->t('@argument title', ['@argument' => $handler->adminLabel()]);
        $options[$optgroup_arguments]["{{ raw_arguments.$arg }}"] = $this->t('@argument input', ['@argument' => $handler->adminLabel()]);
      }

      $this->documentSelfTokens($options[$optgroup_fields]);

      // Default text.
      $output = [];
      $output[] = [
        '#markup' => '<p>' . $this->t('You must add some additional fields to this display before using this field. These fields may be marked as <em>Exclude from display</em> if you prefer. Note that due to rendering order, you cannot use fields that come after this field; if you need a field not listed here, rearrange your fields.') . '</p>',
      ];
      // We have some options, so make a list.       if (!empty($options)) {
        $output[] = [
          '#markup' => '<p>' . $this->t("The following replacement tokens are available for this field. Note that due to rendering order, you cannot use fields that come after this field; if you need a field not listed here, rearrange your fields.") . '</p>',
        ];