verify that path used in twig actually exist

[landsman]

When this extension learn to operate with twig it would be nice to add rule where we can check generated routes agains paths in twig.

<a href="{{ path('some_missing_page') }}">

That would help me a lot on some old projects with checking PRs.

[ruudk]

This can be done by creating a custom Node rule for Twig CS Fixer, see: https://github.com/VincentLanglet/Twig-CS-Fixer/blob/main/docs/custom.md#node-based-rules

[stof]

This would actually be a good rule for https://github.com/twigstan/twigstan once #428 is implemented in this extension