binder_rs: Add Parcelable trait

Adds Parcelable trait that all auto-generated Rust parcelables
implement. This trait provides the get_descriptor() and
get_stability(), as well as internal serialization and
deserialization methods specific to parcelables.

Bug: 169035750
Test: m
Change-Id: Ib97ac4d79cd9829ab3968076492ac1f28f27e8ff
diff --git a/libs/binder/rust/src/parcel.rs b/libs/binder/rust/src/parcel.rs
index dad89ec..8e6c94c 100644
--- a/libs/binder/rust/src/parcel.rs
+++ b/libs/binder/rust/src/parcel.rs
@@ -33,6 +33,7 @@
 pub use self::file_descriptor::ParcelFileDescriptor;
 pub use self::parcelable::{
     Deserialize, DeserializeArray, DeserializeOption, Serialize, SerializeArray, SerializeOption,
+    Parcelable,
 };
 
 /// Container for a message (data and object references) that can be sent