Drop leisure=common (#3619)

This PR drops rendering of leisure=common.

The leisure=common tag has several problems. I therefore think we should not render it on the default style.

Some of these problems are:

* The tag defines a legal ownership concept, not a physical concept. According to the [wiki](https://wiki.openstreetmap.org/wiki/Tag:leisure%3Dcommon), a common is 'land which has an owner, but over which other people have certain rights'. I think we should render the physical appearance or purpose of features rather than their legal status.

* The tag is very UK centric. Commons are a UK concept that does not really translate to other countries.

* The tag is heavily misused. At least in Western Europe, almost all objects tagged with leisure=common are not actually commons. The tag is often used for random pieces of public grass, such as those alongside roads. The fact that the tag renders nicely green on the map probably has something to do with this.

* Other tags are available. Almost all areas that are currently tagged with leisure=common can also be tagged with other tags that are currently being rendered, such as leisure=park, landuse=grass and/or landuse=farmland.

amenity-points.mss

@@ -2385,7 +2385,6 @@
   [feature = 'leisure_recreation_ground'],
   [feature = 'landuse_recreation_ground'],
   [feature = 'landuse_village_green'],
-  [feature = 'leisure_common'],
   [feature = 'leisure_garden'],
   [feature = 'landuse_quarry'],
   [feature = 'landuse_vineyard'],
@@ -2464,7 +2463,6 @@
       [feature = 'leisure_recreation_ground'],
       [feature = 'landuse_recreation_ground'],
       [feature = 'landuse_village_green'],
-      [feature = 'leisure_common'],
       [feature = 'leisure_garden'] {
         text-fill: @leisure-green;
       }

landcover.mss

@@ -1,6 +1,6 @@
 // --- Parks, woods, other green things ---
 
-@grass: #cdebb0;        // Lch(90,32,128) also grassland, meadow, common, village_green, garden
+@grass: #cdebb0;        // Lch(90,32,128) also grassland, meadow, village_green, garden, allotments
 @scrub: #c8d7ab;        // Lch(84,24,122)
 @forest: #add19e;       // Lch(80,30,135)
 @forest-text: #46673b;  // Lch(40,30,135)
@@ -359,8 +359,7 @@
   [feature = 'natural_grassland'][zoom >= 5],
   [feature = 'landuse_meadow'][zoom >= 5],
   [feature = 'landuse_grass'][zoom >= 10],
-  [feature = 'landuse_village_green'][zoom >= 10],
-  [feature = 'leisure_common'][zoom >= 10] {
+  [feature = 'landuse_village_green'][zoom >= 10] {
     polygon-fill: @grass;
     [way_pixels >= 4]  { polygon-gamma: 0.75; }
     [way_pixels >= 64] { polygon-gamma: 0.3;  }

project.mml

@@ -129,7 +129,7 @@ Layer:
                                                     'allotments', 'forest', 'farmyard', 'farmland', 'greenhouse_horticulture',
                                                     'recreation_ground', 'village_green', 'retail', 'industrial', 'railway', 'commercial',
                                                     'brownfield', 'landfill', 'construction', 'plant_nursery', 'religious') THEN landuse ELSE NULL END)) AS landuse,
-              ('leisure_' || (CASE WHEN leisure IN ('swimming_pool', 'playground', 'park', 'recreation_ground', 'common', 'garden',
+              ('leisure_' || (CASE WHEN leisure IN ('swimming_pool', 'playground', 'park', 'recreation_ground', 'garden',
                                                     'golf_course', 'miniature_golf', 'sports_centre', 'stadium', 'pitch', 'ice_rink',
                                                     'track', 'dog_park', 'fitness_station') THEN leisure ELSE NULL END)) AS leisure,
               ('man_made_' || (CASE WHEN man_made IN ('works', 'wastewater_plant', 'water_works') THEN man_made ELSE NULL END)) AS man_made,
@@ -1394,7 +1394,7 @@ Layer:
              AND NOT tags @> 'capital=>yes'
              OR (place IN ('suburb', 'quarter', 'neighbourhood', 'locality', 'isolated_dwelling', 'farm')
                  OR (place IN ('square')
-                     AND (leisure is NULL OR NOT leisure IN ('park', 'common', 'recreation_ground', 'garden')))
+                     AND (leisure is NULL OR NOT leisure IN ('park', 'recreation_ground', 'garden')))
              ) AND name IS NOT NULL
           ORDER BY CASE
               WHEN place = 'suburb' THEN 3
@@ -1934,7 +1934,7 @@ Layer:
                 AND (tunnel NOT IN ('yes', 'building_passage') OR tunnel IS NULL)
                 AND (covered NOT IN ('yes') OR covered IS NULL))
             OR (place IN ('square')
-                AND (leisure IS NULL OR NOT leisure IN ('park', 'common', 'recreation_ground', 'garden')))
+                AND (leisure IS NULL OR NOT leisure IN ('park', 'recreation_ground', 'garden')))
             AND name IS NOT NULL
           ORDER BY way_area DESC
         ) AS roads_area_text_name
@@ -2126,7 +2126,7 @@ Layer:
                               WHEN shop IN ('no', 'vacant', 'closed', 'disused', 'empty') OR shop IS NULL THEN NULL ELSE 'other' END,
               'office' || CASE WHEN tags->'office' IN ('no', 'vacant', 'closed', 'disused', 'empty') OR (tags->'office') IS NULL THEN NULL ELSE '' END,
               'leisure_' || CASE WHEN leisure IN ('swimming_pool', 'water_park', 'miniature_golf', 'golf_course', 'fitness_centre', 'sports_centre', 'stadium', 'track',
-                                                  'pitch', 'playground', 'park', 'recreation_ground', 'common', 'garden', 'nature_reserve', 'marina',
+                                                  'pitch', 'playground', 'park', 'recreation_ground', 'garden', 'nature_reserve', 'marina',
                                                   'picnic_table', 'dog_park', 'fitness_station', 'firepit', 'sauna', 'beach_resort', 'bowling_alley',
                                                   'outdoor_seating', 'bird_hide', 'amusement_arcade', 'swimming_area', 'fishing', 'ice_rink') THEN leisure ELSE NULL END,
               'power_' || CASE WHEN power IN ('plant', 'station', 'generator', 'sub_station', 'substation') THEN power ELSE NULL END,
@@ -2328,7 +2328,7 @@ Layer:
                                   WHEN shop IN ('no', 'vacant', 'closed', 'disused', 'empty') OR shop IS NULL THEN NULL ELSE 'other' END,
                   'office' || CASE WHEN tags->'office' IN ('no', 'vacant', 'closed', 'disused', 'empty') OR (tags->'office') IS NULL THEN NULL ELSE '' END,
                   'leisure_' || CASE WHEN leisure IN ('swimming_pool', 'water_park', 'miniature_golf', 'golf_course', 'fitness_centre', 'sports_centre', 'stadium', 'track',
-                                                      'pitch','playground', 'park', 'recreation_ground', 'common', 'garden', 'nature_reserve', 'marina',
+                                                      'pitch','playground', 'park', 'recreation_ground', 'garden', 'nature_reserve', 'marina',
                                                       'slipway', 'picnic_table', 'dog_park', 'fitness_station', 'firepit', 'sauna', 'beach_resort', 'bowling_alley',
                                                       'outdoor_seating', 'bird_hide', 'amusement_arcade', 'swimming_area', 'fishing', 'ice_rink') THEN leisure ELSE NULL END,
                   'power_' || CASE WHEN power IN ('plant', 'station', 'generator', 'sub_station', 'substation') THEN power ELSE NULL END,