Upgrade regex-syntax to 0.6.29 am: 713de16f11 am: d9f74f32a9 am: 3c4584e4f1 am: 22a53f8bb2

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/regex-syntax/+/2519958

Change-Id: If34761826c018678c44daefb81aa1c2104d8f37f
Signed-off-by: Automerger Merge Worker <[email protected]>