aerialway class for the transportation layer (#1011)

Co-authored-by: Tomas Pohanka <TomPohys@gmail.com>

layers/transportation/layer.sql

@@ -36,7 +36,7 @@ SELECT osm_id,
            WHEN NULLIF(highway, '') IS NOT NULL OR NULLIF(public_transport, '') IS NOT NULL
                THEN highway_class(highway, public_transport, construction)
            WHEN NULLIF(railway, '') IS NOT NULL THEN railway_class(railway)
-           WHEN NULLIF(aerialway, '') IS NOT NULL THEN aerialway
+           WHEN NULLIF(aerialway, '') IS NOT NULL THEN 'aerialway'
            WHEN NULLIF(shipway, '') IS NOT NULL THEN shipway
            WHEN NULLIF(man_made, '') IS NOT NULL THEN man_made
            END AS class,
@@ -45,6 +45,7 @@ SELECT osm_id,
            WHEN (highway IS NOT NULL OR public_transport IS NOT NULL)
                AND highway_class(highway, public_transport, construction) = 'path'
                THEN COALESCE(NULLIF(public_transport, ''), highway)
+           WHEN aerialway IS NOT NULL THEN aerialway
            END AS subclass,
        -- All links are considered as ramps as well
        CASE