fix: address code review findings

internal/routing/graph.go

@@ -1038,8 +1038,6 @@ func SelectHubStations(stations []StationInfo, minOutgoingFlights int) []*Node {
 	return hubs
 }
 
-// getStationNeighbors returns neighboring stations for a given station ID in the same city.
-
 // RouteStatus represents the current status of a route leg.
 type RouteStatus int32