rust: re-export qemu_macros internal helper in "bits"

Avoid the need to import "qemu_macros".

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Link: https://lore.kernel.org/r/20250827104147.717203-21-marcandre.lureau@redhat.com
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

rust/bits/src/lib.rs

@@ -380,14 +380,17 @@ macro_rules! bits {
     };
 
     { $type:ty: $expr:expr } => {
-        ::qemu_macros::bits_const_internal! { $type @ ($expr) }
+        $crate::bits_const_internal! { $type @ ($expr) }
     };
 
     { $type:ty as $int_type:ty: $expr:expr } => {
-        (::qemu_macros::bits_const_internal! { $type @ ($expr) }.into_bits()) as $int_type
+        ($crate::bits_const_internal! { $type @ ($expr) }.into_bits()) as $int_type
     };
 }
 
+#[doc(hidden)]
+pub use qemu_macros::bits_const_internal;
+
 #[cfg(test)]
 mod test {
     bits! {