Sort rustc_middle attributes.

As is already done in several other crates, such as `rustc_errors`.

compiler/rustc_middle/src/lib.rs

@@ -22,44 +22,46 @@
 //!
 //! This API is completely unstable and subject to change.
 
+// tidy-alphabetical-start
+#![allow(internal_features)]
+#![allow(rustc::diagnostic_outside_of_impl)]
+#![allow(rustc::potential_query_instability)]
+#![allow(rustc::untranslatable_diagnostic)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
-#![feature(min_exhaustive_patterns)]
-#![feature(rustdoc_internals)]
 #![feature(allocator_api)]
 #![feature(array_windows)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(closure_track_caller)]
-#![feature(core_intrinsics)]
+#![feature(const_option)]
 #![feature(const_type_name)]
-#![feature(discriminant_kind)]
+#![feature(core_intrinsics)]
 #![feature(coroutines)]
+#![feature(decl_macro)]
+#![feature(discriminant_kind)]
+#![feature(extern_types)]
+#![feature(extract_if)]
 #![feature(if_let_guard)]
 #![feature(intra_doc_pointers)]
 #![feature(iter_from_coroutine)]
+#![feature(let_chains)]
+#![feature(macro_metavar_expr)]
+#![feature(min_exhaustive_patterns)]
+#![feature(min_specialization)]
 #![feature(negative_impls)]
 #![feature(never_type)]
-#![feature(extern_types)]
 #![feature(new_uninit)]
-#![feature(let_chains)]
-#![feature(min_specialization)]
-#![feature(trusted_len)]
-#![feature(type_alias_impl_trait)]
-#![feature(strict_provenance)]
+#![feature(ptr_alignment_type)]
 #![feature(rustc_attrs)]
+#![feature(rustdoc_internals)]
+#![feature(strict_provenance)]
 #![feature(trait_upcasting)]
+#![feature(trusted_len)]
 #![feature(try_blocks)]
-#![feature(decl_macro)]
-#![feature(extract_if)]
+#![feature(type_alias_impl_trait)]
 #![feature(yeet_expr)]
-#![feature(const_option)]
-#![feature(ptr_alignment_type)]
-#![feature(macro_metavar_expr)]
-#![allow(internal_features)]
-#![allow(rustc::potential_query_instability)]
-#![allow(rustc::diagnostic_outside_of_impl)]
-#![allow(rustc::untranslatable_diagnostic)]
+// tidy-alphabetical-end
 
 #[macro_use]
 extern crate tracing;