Voronoi Non-Euclidean Distance Enhancements

Currently, the Distance to Edge mode only works for the Euclidean distance metric.

I was looking through the code for the Voronoi texture, and found the link to shadertoy.com/view/ldl3W8 . From there, I found this: shadertoy.com/view/MtlyR8 , which I think could significantly expand the functionality of the Voronoi node if someone more experienced than myself were to figure out how to port it across.

This shader appears to include that functionality for Manhattan and Chebyshev distance, as well as incorporating a new "Octagonal" distance metric.