Upgrade pest_derive to 2.7.6 am: e78dc39d2e

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/pest_derive/+/2949316

Change-Id: I445d550cbf8858cdeed9647150a38573ac72034c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>