Plot the pairwise nesting index matrix
Source:R/api-hierarchical-audit.R
plot.mfrm_facet_nesting.RdRenders the directed nesting index \(1 - H(B \mid A)/H(B)\) as a heatmap between facet pairs, highlighting fully nested relationships close to 1. Colour scale runs from 0 (crossed, white / cold) to 1 (fully nested, dark).