Allow fmtstr to be passed to static_assert instead of str.

[iAmMichaelConnor]

A minor feature request, if it's even possible.

E.g. to print the values of numeric generics that are being compared with static_assert.

[asterite]

I just looked into this.

For this program:

use std::static_assert;

fn main() {
    let x = 1;
    static_assert(x == 2, "OH NO");
}

we get this error:

error: Argument is false
  ┌─ src/main.nr:5:5
  │
5 │     static_assert(x == 2, "OH NO");
  │     ------------------------------
  │
  = Call stack:
    1. src/main.nr:5:5

Aborting due to 1 previous error

So the message seems to be unused. So first we'd need to display that message, I guess.

But I was wondering, given that we have assert and assert_eq, if it wouldn't make sense to have static_assert_eq instead, and if the two values are different, that would be printed (we'd know the values of the constants so we could easily print those).

[TomAFrench]

related to the above #7005