Mark dirty the catchment of a station on change as necessary for zoning.

If the zoning mode is station catchment, or unserved industry/building,
mark dirty the station catchment rectangle before removing, or after
adding, (a) station tile(s).
In the case of unserved industry mode, increase the refreshed catchment
radius by 10 tiles, to wholly include industries partially inside
the catchment area.

src/zoning.h

@@ -45,4 +45,7 @@ void DrawTileZoning(const TileInfo *ti);
 
 void ShowZoningToolbar();
 
+void ZoningMarkDirtyStationCoverageArea(const Station *st);
+inline void ZoningMarkDirtyStationCoverageArea(const Waypoint *st) { } // no-op
+
 #endif /* ZONING_H */