Mark ab/6881855 as merged am: 8b87033c9a am: b9e26d13e5

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/rust/crates/proc-macro-nested/+/13110708

Change-Id: Ic66e56327fcb074b8173b926f3dc38f3528390ec