Rollup merge of #82113 - m-ou-se:panic-format-lint, r=estebank

Improve non_fmt_panic lint.

This change:
- fixes the span used by this lint in the case the panic argument is a single macro expansion (e.g. `panic!(a!())`);
- adds a suggestion for `panic!(format!(..))` to remove `format!()` instead of adding `"{}", ` or using `panic_any` like it does now; and
- fixes the incorrect suggestion to replace `panic![123]` by `panic_any(123]`.

Fixes #82109.
Fixes #82110.
Fixes #82111.

Example output:
```
warning: panic message is not a string literal
 --> src/main.rs:8:12
  |
8 |     panic!(format!("error: {}", "oh no"));
  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(non_fmt_panic)]` on by default
  = note: this is no longer accepted in Rust 2021
  = note: the panic!() macro supports formatting, so there's no need for the format!() macro here
help: remove the `format!(..)` macro call
  |
8 |     panic!("error: {}", "oh no");
  |           --                  --

```

r? `@estebank`

1 files changed, 1 insertions, 0 deletions

diff --git a/library/alloc/src/macros.rs b/library/alloc/src/macros.rs
index a64a8b32ad7..6a64587a223 100644
--- a/library/alloc/src/macros.rs
+++ b/library/alloc/src/macros.rs
@@ -107,6 +107,7 @@ macro_rules! vec {
 /// ```
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "format_macro")]
 macro_rules! format {
     ($($arg:tt)*) => {{
         let res = $crate::fmt::format($crate::__export::format_args!($($arg)*));