Confusing diagnostic when using format strings in const fn

[nsunderland1]

Reproduced in the Playground on 1.58.1 stable.

Given the following code: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=fe56b4c08a046bd087207e0649379a33

const fn failure() {
    panic!("{:?}", 0);
}

fn main() {}

The current output is:

error[[E0658]](https://doc.rust-lang.org/stable/error-index.html#E0658): function pointer casts are not allowed in constant functions
 [--> src/main.rs:2:20
](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=de5939e5ea116da7ce863563832ea7b9#)  |
2 |     panic!("{:?}", 0);
  |                    ^
  |
  = note: [see issue #57563 <https://github.com/rust-lang/rust/issues/57563>](https://github.com/rust-lang/rust/issues/57563) for more information
  = note: this error originates in the macro `$crate::const_format_args` (in Nightly builds, run with -Z macro-backtrace for more info)

error[[E0015]](https://doc.rust-lang.org/stable/error-index.html#E0015): calls in constant functions are limited to constant functions, tuple structs and tuple variants
 [--> src/main.rs:2:5
](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=de5939e5ea116da7ce863563832ea7b9#)  |
2 |     panic!("{:?}", 0);
  |     ^^^^^^^^^^^^^^^^^
  |
  = note: this error originates in the macro `$crate::const_format_args` (in Nightly builds, run with -Z macro-backtrace for more info)

panic with formatting isn't fully supported in const contexts, but the diagnostic is surprising, since it's not obvious that there are any function pointer casts happening. This should give a more direct message about what I've done wrong.

[oli-obk]

Note that on nightly we only get

error[[E0015]](https://doc.rust-lang.org/nightly/error-index.html#E0015): calls in constant functions are limited to constant functions, tuple structs and tuple variants
 [--> src/main.rs:2:20
](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021#)  |
2 |     panic!("{:?}", 0);
  |                    ^
  |
  = note: this error originates in the macro `$crate::const_format_args` (in Nightly builds, run with -Z macro-backtrace for more info)

without any additional info (but at least the function pointer diagnostic is gone)