Ferry routes layering

This is a rather niche layering problem associated with ferry routes being rendered before waterway bridges, but worth documenting. [Here](https://www.openstreetmap.org/note/2538375#map=19/52.476163/-1.907852): <img width="318" height="255" alt="Image" src="https://github.com/user-attachments/assets/16c2373a-fce8-4ab0-8e91-6a51c126568d" /> (route interrupted by aqueduct) No obvious fix since it does make sense for ferry routes to be rendered before the road network (e.g. bridges over waterways). Note that the ferry routes are mapped as separate ways, i.e. it is not possible to create a separate "ferry route bridges" layer.