Auto merge of rust-lang#108682 - est31:simplify_dirs, r=davidtwco

Simplify message paths

This makes it easier to open the messages file. Right now I have to first click on the `locales` dir to open it, and then on the `en-US.ftl` file. `Cargo.toml` and `build.rs` files are also in the top level, and I think there should not be more than one file, so a directory isn't really needed. The [chosen strategy for pontoon adoption](https://rust-lang.zulipchat.com/#narrow/stream/336883-i18n/topic/pontoon.20and.20next.20steps) is out of tree. Even if this descision is changed in the future, the `messages.ftl` approach is also compatible with non-english translations living in-tree, as long as the non-english translations don't live in the `compiler/rustc_foo/` directories but in different ones. That would also be helpful for grepability purposes.

The commit was the result of automated changes:

```
for p in compiler/rustc_*; do mv $p/locales/en-US.ftl $p/messages.ftl; rmdir $p/locales; done

for p in compiler/rustc_*; do sed -i "s#\.\./locales/en-US.ftl#../messages.ftl#" $p/src/lib.rs; done
```

r? `@davidtwco`

Author: bors

compiler/rustc_ast_lowering/locales/en-US.ftl renamed to compiler/rustc_ast_lowering/messages.ftl

@@ -92,7 +92,7 @@ mod lifetime_collector;
 mod pat;
 mod path;
 
-fluent_messages! { "../locales/en-US.ftl" }
+fluent_messages! { "../messages.ftl" }
 
 struct LoweringContext<'a, 'hir> {
     tcx: TyCtxt<'hir>,

compiler/rustc_ast_lowering/src/lib.rs

@@ -21,4 +21,4 @@ pub mod feature_gate;
 pub mod node_count;
 pub mod show_span;
 
-fluent_messages! { "../locales/en-US.ftl" }
+fluent_messages! { "../messages.ftl" }

compiler/rustc_ast_passes/locales/en-US.ftl renamed to compiler/rustc_ast_passes/messages.ftl

@@ -26,4 +26,4 @@ pub use rustc_ast::attr::*;
 
 pub(crate) use rustc_ast::HashStableContext;
 
-fluent_messages! { "../locales/en-US.ftl" }
+fluent_messages! { "../messages.ftl" }

compiler/rustc_ast_passes/src/lib.rs

@@ -100,7 +100,7 @@ use places_conflict::{places_conflict, PlaceConflictBias};
 use region_infer::RegionInferenceContext;
 use renumber::RegionCtxt;
 
-fluent_messages! { "../locales/en-US.ftl" }
+fluent_messages! { "../messages.ftl" }
 
 // FIXME(eddyb) perhaps move this somewhere more centrally.
 #[derive(Debug)]

compiler/rustc_attr/locales/en-US.ftl renamed to compiler/rustc_attr/messages.ftl

@@ -56,7 +56,7 @@ pub mod proc_macro_harness;
 pub mod standard_library_imports;
 pub mod test_harness;
 
-fluent_messages! { "../locales/en-US.ftl" }
+fluent_messages! { "../messages.ftl" }
 
 pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
     let mut register = |name, kind| resolver.register_builtin_macro(name, kind);