Fix proc-macro-nested/METADATA am: ac50c4e764 am: fc9d0a0dcd am: a0193d3e51 am: 319ecfb7b1

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/proc-macro-nested/+/1413756

Change-Id: I15c0c4fcaba92fe854ff6ecd1c0e1fd86064c77a