Merge "Mark apex-available" into main am: 186e8f9d6c

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/smallvec/+/3165871

Change-Id: I41da9f3343c3ddb4a0ae0fc13d3e7f31b282694b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>