rust: alloc: Rust 1.73 compat fixes

Signed-off-by: Asahi Lina <[email protected]>

Author: hoshinolina

rust/alloc/lib.rs

@@ -57,6 +57,7 @@
 //! [`Cell`]: core::cell
 //! [`Rc`]: rc
 //! [`RefCell`]: core::cell
+#![feature(doc_cfg_hide)]
 
 #![allow(unused_attributes)]
 #![stable(feature = "alloc", since = "1.36.0")]
@@ -109,7 +110,7 @@
 #![feature(cfg_version)]
 #![feature(coerce_unsized)]
 #![feature(const_align_of_val)]
-#![feature(const_box)]
+#![cfg_attr(not(version("1.73")), feature(const_box))]
 #![cfg_attr(not(no_borrow), feature(const_cow_is_borrowed))]
 #![feature(const_eval_select)]
 #![feature(const_maybe_uninit_as_mut_ptr)]
@@ -140,7 +141,7 @@
 #![feature(maybe_uninit_uninit_array_transpose)]
 #![feature(pattern)]
 #![feature(pointer_byte_offsets)]
-#![feature(provide_any)]
+#![cfg_attr(not(version("1.73")), feature(provide_any))]
 #![feature(ptr_internals)]
 #![feature(ptr_metadata)]
 #![feature(ptr_sub_ptr)]
@@ -203,7 +204,6 @@
 //
 // Rustdoc features:
 #![feature(doc_cfg)]
-#![feature(doc_cfg_hide)]
 // Technically, this is a bug in rustdoc: rustdoc sees the documentation on `#[lang = slice_alloc]`
 // blocks is for `&[T]`, which also has documentation using this feature in `core`, and gets mad
 // that the feature-gate isn't enabled. Ideally, it wouldn't check for the feature gate for docs