Auto merge of #86603 - Mark-Simulacrum:stage-step, r=pietroalbini

Update to new bootstrap compiler

r? `@pietroalbini`

compiler/rustc_ast/src/lib.rs

@@ -10,7 +10,6 @@
 )]
 #![feature(box_syntax)]
 #![feature(box_patterns)]
-#![cfg_attr(bootstrap, feature(const_fn_unsize))]
 #![feature(const_fn_transmute)]
 #![feature(crate_visibility_modifier)]
 #![feature(iter_zip)]

compiler/rustc_codegen_llvm/src/lib.rs

@@ -8,7 +8,6 @@
 #![feature(bool_to_option)]
 #![feature(const_cstr_unchecked)]
 #![feature(crate_visibility_modifier)]
-#![cfg_attr(bootstrap, feature(extended_key_value_attributes))]
 #![feature(extern_types)]
 #![feature(in_band_lifetimes)]
 #![feature(iter_zip)]

compiler/rustc_errors/src/lib.rs

@@ -5,7 +5,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(crate_visibility_modifier)]
 #![feature(backtrace)]
-#![cfg_attr(bootstrap, feature(extended_key_value_attributes))]
 #![feature(format_args_capture)]
 #![feature(iter_zip)]
 #![feature(nll)]

compiler/rustc_hir/src/lib.rs

@@ -3,7 +3,6 @@
 //! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
 
 #![feature(crate_visibility_modifier)]
-#![cfg_attr(bootstrap, feature(extended_key_value_attributes))]
 #![feature(in_band_lifetimes)]
 #![feature(once_cell)]
 #![feature(min_specialization)]