Add `#![allow(non_upper_case_globals)]` to the generated `.rs` files.

Before this CL, Rust might warn about some C++ identifiers in the
generated Rust bindings.  For example:

```stderr
warning: associated constant `kRed` should have an upper case name
   --> crubit/rs_bindings_from_cc/test/golden/types_cc_rust_api.rs:217:15
    |
217 |     pub const kRed: Color = Color(0);
    |               ^^^^ help: convert the identifier to upper case: `K_RED`
    |
    = note: `#[warn(non_upper_case_globals)]` on by default
```

After this CL, such warnings are disabled.

PiperOrigin-RevId: 448320338
diff --git a/rs_bindings_from_cc/src_code_gen.rs b/rs_bindings_from_cc/src_code_gen.rs
index ee99178..ded730a 100644
--- a/rs_bindings_from_cc/src_code_gen.rs
+++ b/rs_bindings_from_cc/src_code_gen.rs
@@ -1527,7 +1527,8 @@
         rs_api: quote! {
             #features __NEWLINE__
             #![allow(non_camel_case_types)] __NEWLINE__
-            #![allow(non_snake_case)] __NEWLINE__ __NEWLINE__
+            #![allow(non_snake_case)] __NEWLINE__
+            #![allow(non_upper_case_globals)] __NEWLINE__ __NEWLINE__
 
             #imports __NEWLINE__ __NEWLINE__
 
diff --git a/rs_bindings_from_cc/test/golden/clang_attrs_rs_api.rs b/rs_bindings_from_cc/test/golden/clang_attrs_rs_api.rs
index dd6b4f3..8946740 100644
--- a/rs_bindings_from_cc/test/golden/clang_attrs_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/clang_attrs_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes, negative_impls)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/comment_rs_api.rs b/rs_bindings_from_cc/test/golden/comment_rs_api.rs
index 0b089b2..c4c319c 100644
--- a/rs_bindings_from_cc/test/golden/comment_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/comment_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/doc_comment_rs_api.rs b/rs_bindings_from_cc/test/golden/doc_comment_rs_api.rs
index cc47eec..fe1fc72 100644
--- a/rs_bindings_from_cc/test/golden/doc_comment_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/doc_comment_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api.rs b/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api.rs
index 7846092..cc26607 100644
--- a/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/inheritance_rs_api.rs b/rs_bindings_from_cc/test/golden/inheritance_rs_api.rs
index a88b287..05b3350 100644
--- a/rs_bindings_from_cc/test/golden/inheritance_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/inheritance_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes, negative_impls)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/item_order_rs_api.rs b/rs_bindings_from_cc/test/golden/item_order_rs_api.rs
index b589919..cb854de 100644
--- a/rs_bindings_from_cc/test/golden/item_order_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/item_order_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/lifetimes_rs_api.rs b/rs_bindings_from_cc/test/golden/lifetimes_rs_api.rs
index 9715b34..84c6048 100644
--- a/rs_bindings_from_cc/test/golden/lifetimes_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/lifetimes_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 
diff --git a/rs_bindings_from_cc/test/golden/namespace_rs_api.rs b/rs_bindings_from_cc/test/golden/namespace_rs_api.rs
index 0815592..e04cf8d 100644
--- a/rs_bindings_from_cc/test/golden/namespace_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/namespace_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes, negative_impls)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api.rs b/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api.rs
index 89eed7d..f861ebd 100644
--- a/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api.rs b/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api.rs
index e02ea22..e5310be 100644
--- a/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes, negative_impls, type_alias_impl_trait)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/polymorphic_rs_api.rs b/rs_bindings_from_cc/test/golden/polymorphic_rs_api.rs
index d957482..1579f1e 100644
--- a/rs_bindings_from_cc/test/golden/polymorphic_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/polymorphic_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes, negative_impls, type_alias_impl_trait)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/private_members_rs_api.rs b/rs_bindings_from_cc/test/golden/private_members_rs_api.rs
index ee1bdc2..cc99a9b 100644
--- a/rs_bindings_from_cc/test/golden/private_members_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/private_members_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/static_methods_rs_api.rs b/rs_bindings_from_cc/test/golden/static_methods_rs_api.rs
index f0548f3..9806b99 100644
--- a/rs_bindings_from_cc/test/golden/static_methods_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/static_methods_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/trivial_type_rs_api.rs b/rs_bindings_from_cc/test/golden/trivial_type_rs_api.rs
index 24a2bc5..a9b56ba 100644
--- a/rs_bindings_from_cc/test/golden/trivial_type_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/trivial_type_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes, negative_impls, type_alias_impl_trait)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/types_rs_api.rs b/rs_bindings_from_cc/test/golden/types_rs_api.rs
index cb8db62..59c710b 100644
--- a/rs_bindings_from_cc/test/golden/types_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/types_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/unnamed_fields_rs_api.rs b/rs_bindings_from_cc/test/golden/unnamed_fields_rs_api.rs
index 2f48f5c..405a42e 100644
--- a/rs_bindings_from_cc/test/golden/unnamed_fields_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/unnamed_fields_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes, negative_impls)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/unsupported_rs_api.rs b/rs_bindings_from_cc/test/golden/unsupported_rs_api.rs
index 529cc0d..5bbd562 100644
--- a/rs_bindings_from_cc/test/golden/unsupported_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/unsupported_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes, negative_impls, type_alias_impl_trait)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api.rs b/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api.rs
index b75edba..61d0767 100644
--- a/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes, negative_impls)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api.rs b/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api.rs
index f6cbcdd..413bb84 100644
--- a/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(const_ptr_offset_from, custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;
 use memoffset_unstable_const::offset_of;
diff --git a/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api.rs b/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api.rs
index 1ca30dd..0e4ae86 100644
--- a/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api.rs
@@ -8,6 +8,7 @@
 #![feature(custom_inner_attributes)]
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
+#![allow(non_upper_case_globals)]
 
 use ::std as rust_std;