Restored default HeatMapPlot nan color to white

holoviews/plotting/mpl/raster.py

@@ -90,6 +90,14 @@ def update_handles(self, key, axis, element, ranges, style):
 
 class HeatMapPlot(RasterPlot):
 
+    clipping_colors = param.Dict(default={'NaN': (1, 1, 1, 1)}, doc="""
+        Dictionary to specify colors for clipped values, allows
+        setting color for NaN values and for values above and below
+        the min and max value. The min, max or NaN color may specify
+        an RGB(A) color as a color hex string of the form #FFFFFF or
+        #FFFFFFFF or a length 3 or length 4 tuple specifying values in
+        the range 0-1 or a named HTML color.""")
+
     show_values = param.Boolean(default=False, doc="""
         Whether to annotate each pixel with its value.""")