PolyAnnotation: link reference guide to user guide
@@ -859,6 +859,9 @@ class LabelSet(TextAnnotation): # TODO: DataAnnotation
class PolyAnnotation(Annotation):
''' Render a shaded polygonal region as an annotation.
+ See :ref:`userguide_plotting_polygon_annotations` for information on
+ plotting polygon annotations.
+
'''
xs = Seq(Float, default=[], help="""
