Rollup merge of rust-lang#99438 - WaffleLapkin:dont_wrap_in_non_zero, r=compiler-errors

Improve suggestions for `NonZeroT` <- `T` coercion error

Currently, when encountering a type mismatch error with `NonZeroT` and `T` (for example `NonZeroU8` and `u8`) we errorneusly suggest wrapping expression in `NonZeroT`:
```text
error[E0308]: mismatched types
 --> ./t.rs:7:35
  |
7 |     let _: std::num::NonZeroU64 = 1;
  |            --------------------   ^ expected struct `NonZeroU64`, found integer
  |            |
  |            expected due to this
  |
help: try wrapping the expression in `std::num::NonZeroU64`
  |
7 |     let _: std::num::NonZeroU64 = std::num::NonZeroU64(1);
  |                                   +++++++++++++++++++++ +
```

I've removed this suggestion and added suggestions to call `new` (for `Option<NonZeroT>` <- `T` case) or `new` and `unwrap` (for `NonZeroT` <- `T` case):

```text
error[E0308]: mismatched types
 --> ./t.rs:7:35
  |
7 |     let _: std::num::NonZeroU64 = 1;
  |            --------------------   ^ expected struct `NonZeroU64`, found integer
  |            |
  |            expected due to this
  |
help: Consider calling `NonZeroU64::new`
  |
7 |     let _: std::num::NonZeroU64 = NonZeroU64::new(1).unwrap();
  |                                   ++++++++++++++++ ++++++++++

error[E0308]: mismatched types
 --> ./t.rs:8:43
  |
8 |     let _: Option<std::num::NonZeroU64> = 1;
  |            ----------------------------   ^ expected enum `Option`, found integer
  |            |
  |            expected due to this
  |
  = note: expected enum `Option<NonZeroU64>`
             found type `{integer}`
help: Consider calling `NonZeroU64::new`
  |
8 |     let _: Option<std::num::NonZeroU64> = NonZeroU64::new(1);
  |                                           ++++++++++++++++ +
```

r? `@compiler-errors`

Author: matthiaskrgr

core/src/num/nonzero.rs

@@ -39,6 +39,7 @@ macro_rules! nonzero_integers {
             #[repr(transparent)]
             #[rustc_layout_scalar_valid_range_start(1)]
             #[rustc_nonnull_optimization_guaranteed]
+            #[rustc_diagnostic_item = stringify!($Ty)]
             pub struct $Ty($Int);
 
             impl $Ty {