Description
Add a route path (URL pattern) to the returned URL matcher parameters. Currently, UrlMatcher returns an array (example from demo app):

[
  "_route" => "blog_index",
  "page" => "1",
  "_format" => "html",
  "_controller" => "App\Controller\BlogController::index",
  "_locale" => "fr"
]

But sometimes the route pattern is needed (like /{_locale}/blog/).

Example
The real use case is: my client wants the integration of a site monitoring system with Symfony, and wants to group information of each request by URL patterns. Currently, there's no other way to get route path pattern except using Router::getRouteCollection() which is not recommended. Also, Router::match() leads to Twig related exception in the demo app:

An exception has been thrown during the rendering of a template ("No routes found for "/_fragment/".").

To reproduce a Twig exception, you need to set up a demo app, create an event listener that is executed before RouterListener (e.g. priority 9999), inject Router, and execute $this->router->match($request->getPathInfo()); on kernel.request event