Remove sanctuary-def, predicated modules and yslashn's nFold.
I'm not personally using these modules. The point of this project is to experiment and dog-food API's, but I can't do that if I'm not getting value out of them in real world projects.
I've learned taggy and yslashn are mostly all I need day to day. And within yslashn I don't use nFold anymore. The only code I have that uses nFold predates the existence of taggy.
That leaves only 3 modules that potentially can become 1 interface, and eventually replace https://github.com/JAForbes/sum-type.
The functionality I'm proposing to be removed is easy to recreate as separate libraries if someone finds value in doing so.