Fix documentation

Author: martinRenou

docs/source/api_reference/local_tile_layer.rst

@@ -9,15 +9,21 @@ Example
     from ipyleaflet import Map, LocalTileLayer
 
     m = Map(center=(52.204793, 360.121558), zoom=9)
-    m.add_layer(LocalTileLayer(url='./tiles/{z}/{x}/{y}.png'))
+    m.add_layer(LocalTileLayer(path='tiles/{z}/{x}/{y}.png'))
 
     m
 
+Note that the behavior is different in Jupyter Notebook and in JupyterLab.
+
+In the classic Jupyter Notebook, the path is relative to the Notebook you are working on.
+
+In JupyterLab, the path is relative to the server (where you started JupyterLab) and you need to prefix the path with "files/".
+
 Attributes
 ----------
 
 ===============    =================  =====
 Attribute          Default Value      Doc
 ===============    =================  =====
-url                ""                 Relative URL (e.g. './tiles/{z}/{x}/{y}.png')
+path               ""                 Relative URL (e.g. 'tiles/{z}/{x}/{y}.png' or 'files/tiles/{z}/{x}/{y}.png' in JupyterLab)
 ===============    =================  =====