Mark the starting point on the first-map supermarket map.

Author: Nathaniel Henry

docs/tutorials/first_map.md

@@ -85,7 +85,8 @@ close_map(
     nearby_supermarkets,
     color = "#e8590c",
     boundary = city_boundary,
-    label = "name"
+    label = "name",
+    mark = (start_lon, start_lat)
 )
 ```