Library exclusively intended to inject UB into safe Rust.

Quoting from the crate description:

> This crate is created purely to inject undefined behavior into stable, safe rust.

Specifically, the `inconceivable!` macro is insta-UB if the `ub_inconceivable` feature is enabled by *any* reverse dependency.
The value this adds is questionable, and hides `unsafe` code from naive analysis.