add etldoc to layer_highway_name

layers/highway_name/merge_highways.sql

@@ -2,6 +2,8 @@
 -- stitch together the touching ways with the same name
 -- to allow for nice label rendering
 -- Because this works well for roads that do not have relations as well
+
+-- etldoc: osm_highway_linestring ->  osm_highway_name_linestring
 CREATE TABLE IF NOT EXISTS osm_highway_name_linestring AS (
 	SELECT
 		(ST_Dump(geometry)).geom AS geometry,
@@ -30,6 +32,7 @@ CREATE TABLE IF NOT EXISTS osm_highway_name_linestring AS (
 
 CREATE INDEX IF NOT EXISTS osm_highway_name_linestring_geometry_idx ON osm_highway_name_linestring USING gist(geometry);
 
+-- etldoc: osm_highway_name_linestring -> osm_highway_name_linestring_gen1 
 CREATE TABLE IF NOT EXISTS osm_highway_name_linestring_gen1 AS (
     SELECT ST_Simplify(geometry, 50) AS geometry, osm_id, member_osm_ids, name, ref, highway, z_order
     FROM osm_highway_name_linestring
@@ -37,6 +40,7 @@ CREATE TABLE IF NOT EXISTS osm_highway_name_linestring_gen1 AS (
 );
 CREATE INDEX IF NOT EXISTS osm_highway_name_linestring_gen1_geometry_idx ON osm_highway_name_linestring_gen1 USING gist(geometry);
 
+-- etldoc: osm_highway_name_linestring_gen1 -> osm_highway_name_linestring_gen2
 CREATE TABLE IF NOT EXISTS osm_highway_name_linestring_gen2 AS (
     SELECT ST_Simplify(geometry, 120) AS geometry, osm_id, member_osm_ids, name, ref, highway, z_order
     FROM osm_highway_name_linestring_gen1
@@ -44,6 +48,7 @@ CREATE TABLE IF NOT EXISTS osm_highway_name_linestring_gen2 AS (
 );
 CREATE INDEX IF NOT EXISTS osm_highway_name_linestring_gen2_geometry_idx ON osm_highway_name_linestring_gen2 USING gist(geometry);
 
+-- etldoc: osm_highway_name_linestring_gen2 -> osm_highway_name_linestring_gen3
 CREATE TABLE IF NOT EXISTS osm_highway_name_linestring_gen3 AS (
     SELECT ST_Simplify(geometry, 120) AS geometry, osm_id, member_osm_ids, name, ref, highway, z_order
     FROM osm_highway_name_linestring_gen2