Fixes link in Flyte and Python Types docs (#1185)

DOC Fixes link in Flyte and Python Types docs

Signed-off-by: Thomas J. Fan <[email protected]>

examples/data_types_and_io/data_types_and_io/flyte_python_types.py

@@ -96,6 +96,6 @@
 #    * - User defined types
 #      - Any
 #      - Custom Transformers
-#      - Use python 3 type hints. We use ``FlytePickle transformer`` by default, but users still can provide custom transformers. Refer to {ref}`advanced_custom_types`.
+#      - Use python 3 type hints. We use ``FlytePickle transformer`` by default, but users still can provide custom transformers. Refer to :ref:`advanced_custom_types`.
 # ```
 #