Bus lanes with a center turn lane break

[dabreegster]

lanes:both_ways=1 and something like bus:lanes:backward=||designated don't work together, due to

osm2lanes/osm2lanes/src/transform/tags_to_lanes/modes/bus/mod.rs

Line 153 in 7f64330

if forward.len().checked_add(backward.len()) != Some(road.len()) {

counting the both-ways lane in road.len().

Example is https://www.openstreetmap.org/way/753045259