Fix typo

Author: JamesGardiner

folium/plugins/fast_marker_cluster.py

@@ -21,7 +21,7 @@ def __init__(self, data, callback=None):
            Be aware that the FastMarkerCluster class passes an empty
            list to the parent class' __init__ method during initialisation.
            This means that the add_child method is never called, and
-           no reference to any marker data are retained. Methids such
+           no reference to any marker data are retained. Methods such
            as get_bounds() are therefore not available when using it.
 
         Parameters