Stabilize const_cstr_unchecked

Author: sugar700

std/src/ffi/c_str.rs

@@ -1259,7 +1259,7 @@ impl CStr {
     #[inline]
     #[must_use]
     #[stable(feature = "cstr_from_bytes", since = "1.10.0")]
-    #[rustc_const_unstable(feature = "const_cstr_unchecked", issue = "90343")]
+    #[rustc_const_stable(feature = "const_cstr_unchecked", since = "1.59.0")]
     pub const unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
         // SAFETY: Casting to CStr is safe because its internal representation
         // is a [u8] too (safe only inside std).

std/src/lib.rs

@@ -252,7 +252,6 @@
 #![feature(char_internals)]
 #![cfg_attr(not(bootstrap), feature(concat_bytes))]
 #![feature(concat_idents)]
-#![feature(const_cstr_unchecked)]
 #![feature(const_fn_floating_point_arithmetic)]
 #![feature(const_fn_fn_ptr_basics)]
 #![feature(const_fn_trait_bound)]