Parse unparenthesized half-open range patterns inside slice patterns

- Tracking issue: https://github.com/rust-lang/rust/issues/67264
- Feature gate: `#![feature(half_open_range_patterns_in_slices)]`

https://github.com/rust-lang/rust/blob/be01dabfefd2daa4574b974f571c7852085d60cb/tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.rs#L42C9-L42C25

```rust
match x {
&[1..] => {}
_ => {}
}
```

Syn currently rejects this syntax.

```console
error: range pattern is not allowed unparenthesized inside slice pattern
--> tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.rs:42:12
|
42 | &[1..] => false,
| ^^
```