Set #![allow(nonstandard_style)] at the top level of our codegen crates.

Right now we generally hit warnings only in cases where someone used non-style-conformant names in their .proto, but warnings on rs codegen aren't the greatest way to surface those and it results in a lot of spam on our tests that intentionally violate the style guide.

PiperOrigin-RevId: 713742680

src/google/protobuf/compiler/rust/generator.cc

@@ -120,10 +120,10 @@ void EmitEntryPointRsFile(GeneratorContext* generator_context,
               {"mod_name", RustInternalModuleName(*file)}},
              R"rs(
               #[path="$file_path$"]
-              #[allow(non_snake_case)]
+              #[allow(nonstandard_style)]
               pub mod internal_do_not_use_$mod_name$;
 
-              #[allow(unused_imports)]
+              #[allow(unused_imports, nonstandard_style)]
               pub use internal_do_not_use_$mod_name$::*;
             )rs");
   }