ad300b6738
Stabilize `proc_macro_byte_character` and `proc_macro_c_str_literals`
This PR stabilizes `proc_macro_byte_character` and `proc_macro_c_str_literals`:
```rust
// proc_macro::Literal
impl Literal {
pub fn byte_character(byte: u8) -> Literal;
pub fn c_string(string: &CStr) -> Literal
}
```
<br>
Tracking issue: https://github.com/rust-lang/rust/issues/115268, https://github.com/rust-lang/rust/issues/119750.
Implementation PR: https://github.com/rust-lang/rust/pull/112711, https://github.com/rust-lang/rust/pull/119651.
FCPs already completed in their respective tracking issues.
Closes https://github.com/rust-lang/rust/issues/115268. Closes https://github.com/rust-lang/rust/issues/119750.
r? libs-api