One patch! macro to rule them all

[kotauskas]

Currently there's the patch* functions which accept from 0 to 9 arguments, which is a limitation when it comes to a larger amount, which is surely non-idiomatic and not practical but can sometimes happen in FFI scenarios. Aside of that, the numbering just looks ugly. A patch! macro (likely implemented as a tiny separate crate decoupled from the patch guard and then reexported in the main crate because that's how proc-macro crates work) is a much cleaner way, I think.

[Ryan Leckey]

I don't disagree here. I'd be willing to accept a PR that did this.