Support snapping to multiple ways at an input location (#5953)

This PR improves routing results by adding support for snapping to
multiple ways at input locations.

This means all edges at the snapped location can act as source/target
candidates for routing search, ensuring we always find the best route,
and not the one dependent on the edge selected.

src/engine/plugins/nearest.cpp

@@ -1,10 +1,7 @@
 #include "engine/plugins/nearest.hpp"
 #include "engine/api/nearest_api.hpp"
 #include "engine/api/nearest_parameters.hpp"
-#include "engine/phantom_node.hpp"
-#include "util/integer_range.hpp"
 
-#include <cstddef>
 #include <string>
 
 #include <boost/assert.hpp>