Show in REST API

[janboddez]

Like this, sort of.

public function register_meta() {
  $options = $this->options_handler->get_options();
  $post_types = $options['post_types'] ?? [];

  foreach ( $post_types as $post_type ) {
    register_post_meta( $post_type, '_share_on_mastodon_url', [
      'single'       => true,
      'show_in_rest' => true,
      'type'         => 'string',
    ] );
  }
}