Does not route on or snap to area highways that are relations.

Ahoj,

while cycle.travel snaps to and calculates routes along the edges of area highways (even to `highway=footway` and `area=yes`), it fails to do so if the area highway is defined as a relation.

See for example this route.

The plaza in the centre is this OSM entity, and it is not possible to snap at it's edge (I tried at the north edge). It also does not route along it. Instead, it snaps to this OSM entity (an area highway not defined as relation).

This also results in a detour, see attached screenshot.

GraphHopper, OSRM, BRouter and OpenRouteService all have the same issue:

* https://github.com/graphhopper/graphhopper/issues/3104
* https://github.com/Project-OSRM/osrm-backend/issues/7146
* https://github.com/abrensch/brouter/issues/778
* https://github.com/GIScience/openrouteservice/issues/1944

Regards!