DOC: add transform links to scale resolve user guide
@@ -75,7 +75,8 @@ each layer.
alt.layer(line_A, line_B).resolve_scale(y='independent')
In this case the axis colors act as a pseudo-legend. Alternatively if you want
-a legend some transformations must be applied. Legends are only created in
+a legend the :ref:`user-guide-filter-transform` and
+:ref:`user-guide-fold-transform` be applied. Legends are only created in
Vega-Lite to represent an encoding.
.. altair-plot::
