docs: fix broken link to Leaflet's class extension tutorial

Author: xecanto

docs/advanced_guide/override_leaflet_class_methods.md

@@ -9,7 +9,7 @@ import folium
 
 ## Customizing Leaflet behavior
 Sometimes you want to override Leaflet's javascript behavior. This can be done using the `Class.include` statement. This mimics Leaflet's
-`L.Class.include` method. See [here](https://leafletjs.com/examples/extending-1-classes/) for more details.
+`L.Class.include` method. See [here](https://leafletjs.com/examples/extending/extending-1-classes.html) for more details.
 
 ### Example: adding an authentication header to a TileLayer
 One such use case is if you need to override the `createTile` on `L.TileLayer`, because your tiles are hosted on an oauth2 protected