fix: make bitflags macro publicly accessible from generated bindings

Changed pub(crate) use bitflags; to pub use bitflags::bitflags; in the
embedded wit_bindgen runtime. This allows external crates that depend on
the generated bindings to access the bitflags macro when they use WASI
filesystem interfaces.

The pub(crate) visibility restricted access to within the bindings crate
itself, preventing downstream users from accessing the macro through the
expected path: crate::wit_bindgen::rt::bitflags::bitflags!

Tested with:
- //examples/basic:hello_component_bindings_host (native-guest mode)
- //tools/checksum_updater_wasm:checksum_updater_wasm_component (WASI filesystem)

Author: avrabe

rust/rust_wasm_component_bindgen.bzl

@@ -160,9 +160,9 @@ pub mod wit_bindgen {
 
         // Bitflags module for WASI interfaces
         pub mod bitflags {
-            // Re-export bitflags macro without #[macro_export]
+            // Re-export bitflags macro for public access from other crates
             // Generated code expects: crate::wit_bindgen::rt::bitflags::bitflags!
-            pub(crate) use bitflags;
+            pub use bitflags::bitflags;
         }
     }
 }
@@ -254,9 +254,9 @@ pub mod wit_bindgen {
 
         // Bitflags module for WASI interfaces
         pub mod bitflags {
-            // Re-export bitflags macro without #[macro_export]
+            // Re-export bitflags macro for public access from other crates
             // Generated code expects: crate::wit_bindgen::rt::bitflags::bitflags!
-            pub(crate) use bitflags;
+            pub use bitflags::bitflags;
         }
     }
 }