Rollup merge of #72534 - chrissimpkins:fix-72373, r=estebank

Improve missing `@` in slice binding pattern diagnostics

Closes https://github.com/rust-lang/rust/issues/72373

Includes a new suggestion with `Applicability::MaybeIncorrect` confidence level.

Before:

```
 --> src/main.rs:5:19
  |
5 |         [h, ref ts..] => foo(c, n - h) + foo(ts, n),
  |                   -^
  |                   |
  |                   expected one of `,`, `@`, `]`, or `|`
  |                   help: missing `,`

error[E0308]: mismatched types
 --> src/main.rs:5:46
  |
5 |         [h, ref ts..] => foo(c, n - h) + foo(ts, n),
  |                                              ^^ expected slice `[u32]`, found `u32`
  |
  = note: expected reference `&[u32]`
             found reference `&u32`

error: aborting due to 2 previous errors
```

After:

```
error: expected one of `,`, `@`, `]`, or `|`, found `..`
 --> src/main.rs:5:20
  |
5 |         [h, ref ts..] => foo(c, n - h) + foo(ts, n),
  |                    ^^ expected one of `,`, `@`, `]`, or `|`
  |
help: if you meant to bind the contents of the rest of the array pattern into `ts`, use `@`
  |
5 |         [h, ref ts @ ..] => foo(c, n - h) + foo(ts, n),
  |                    ^

error: aborting due to previous error
```

r? @estebank

0 files changed, 0 insertions, 0 deletions