Implement Debug for a few Binder Rust types

Test: mmma system/security/keystore2
Change-Id: I6d5413366dd258a1cef887908f98bfb130103943
diff --git a/libs/binder/rust/src/binder.rs b/libs/binder/rust/src/binder.rs
index d55eafe..9cfa589 100644
--- a/libs/binder/rust/src/binder.rs
+++ b/libs/binder/rust/src/binder.rs
@@ -581,5 +581,11 @@
                 parcel.write(&this.map($crate::Interface::as_binder))
             }
         }
+
+        impl std::fmt::Debug for dyn $interface {
+            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+                f.pad(stringify!($interface))
+            }
+        }
     };
 }