Correct a typo in flask example
@@ -3,7 +3,7 @@ Using folium with flask
A very common use case is to use folium with in a flask app.
The trick is to return folium's HTML representation.
-Here is an example on how to d that:
+Here is an example on how to do that:
.. literalinclude:: ../examples/flask_example.py
\ No newline at end of file
