Upgrade rust/crates/regex-syntax to 0.6.23 am: 6f928bfd50 am: fa99334ded am: 36d9b48fbe am: 9680965206

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/regex-syntax/+/1663040

Change-Id: Ifedcd7e55c94d3d0a63c753752da4996000f0986