Rollup merge of #102719 - Nilstrieb:tidy-alphabetical, r=jackh726

Enforce alphabetical sorting with tidy

We have many places where things are supposed to be sorted alphabetically. For the smaller and more recent size assertions, this is mostly upheld, but in other more... alive places it's very messy.

This introduces a new tidy directive to check that a section of code is sorted alphabetically and fixes all places where sorting has gone wrong.

compiler/rustc_error_messages/src/lib.rs

@@ -35,6 +35,7 @@ pub use unic_langid::{langid, LanguageIdentifier};
 
 // Generates `DEFAULT_LOCALE_RESOURCES` static and `fluent_generated` module.
 fluent_messages! {
+    // tidy-alphabetical-start
     ast_lowering => "../locales/en-US/ast_lowering.ftl",
     ast_passes => "../locales/en-US/ast_passes.ftl",
     attr => "../locales/en-US/attr.ftl",
@@ -64,6 +65,7 @@ fluent_messages! {
     symbol_mangling => "../locales/en-US/symbol_mangling.ftl",
     trait_selection => "../locales/en-US/trait_selection.ftl",
     ty_utils => "../locales/en-US/ty_utils.ftl",
+    // tidy-alphabetical-end
 }
 
 pub use fluent_generated::{self as fluent, DEFAULT_LOCALE_RESOURCES};