Add borough to supported place classes (#1470)

Adds a new class value for the place layer, `borough`, and adds it to the OSM style with the same appearance as hamlets and suburbs.

layers/place/mapping.yaml

@@ -177,6 +177,7 @@ tables:
       - town
       - village
       - hamlet
+      - borough
       - suburb
       - quarter
       - neighbourhood

layers/place/place.yaml

@@ -38,6 +38,7 @@ layer:
       - town
       - village
       - hamlet
+      - borough
       - suburb
       - quarter
       - neighbourhood

layers/place/style.json

@@ -82,7 +82,8 @@
           "island",
           "islet",
           "neighbourhood",
-          "suburb"
+          "suburb",
+          "borough"
         ]
       ],
       "order": 193

layers/place/types.sql

@@ -4,7 +4,7 @@ $$
         PERFORM 'city_place'::regtype;
     EXCEPTION
         WHEN undefined_object THEN
-            CREATE TYPE city_place AS enum ('city', 'town', 'village', 'hamlet', 'suburb', 'quarter', 'neighbourhood', 'isolated_dwelling');
+            CREATE TYPE city_place AS enum ('city', 'town', 'village', 'hamlet', 'borough', 'suburb', 'quarter', 'neighbourhood', 'isolated_dwelling');
     END
 $$;