Warn when Unit is used where () is expected

Failing that, I can absolutely see something like Unit.value as a synonym for ().

My intuition when invoking a method with () as the sole parameter is that the parentheses would just collapse like they do in algebra, and I’m sure I can’t be alone here - it just doesn’t look at all right or parse well.

A way to express the concept that isn’t pure syntax would be a definite win.