Group Content not working with Gutenberg

I made this patch that seems to work when combined with a hook implementation in a custom module.

The hook implementation in custom module (along with patch):

/**
 * Implements hook_gutenberg_node_type_route().
 */
function www_core_gutenberg_node_type_route(RouteMatchInterface $route_match) {
  //Get Gutenberg node type from group content routes.
  $route_name = $route_match->getRouteName();
  if ($route_name == 'entity.group_relationship.create_form' || $route_name == 'entity.group_relationship.edit_form') {
    /** @var string $parameter */
    $parameter = $route_match->getParameter('plugin_id');
    return explode(':', $parameter)[1];
  }

  return NULL;
}

IIRC the current example on the gutenberg.api file was made for Group 2.x. I guess it makes sense to update it to 3.x.
Could you provide a MR for it? It would be easier to review 😉

Created MR for 3.x. Kindly review

Merged. Thank you.

Automatically closed - issue fixed for 2 weeks with no activity.