export class_inherits()?

[lawremi]

class_inherits() is a useful utility for checking whether an object satisfies a class specification. I use the term specification, because I am not sure things like a class union or class_any are really classes (both are types of unions). But the fact that it's a specification makes it different from inherits().

Should we export it? The name seems OK. In fact, it's better than inherits(), because objects do not inherit, classes do.

We could also use something like class_satisfies() to distinguish it from inherits().