third-party/rust: update cbindgen to upstream git repo

Summary:
PRs mozilla/cbindgen#1006
mozilla/cbindgen#1007 were accepted, so update patch to
upstream git repo until next release is cut.

Also bump `syn` to match cbindgen.

Reviewed By: dtolnay

Differential Revision: D65079945

fbshipit-source-id: 5b9f0467150d7cf81f5a9df0bb4d0c1309e67e1b

Author: Jeremy Fitzhardinge

Cargo.lock

@@ -32,7 +32,7 @@ serde = { version = "1.0.185", features = ["derive", "rc"] }
 serde_json = { version = "1.0.125", features = ["float_roundtrip", "unbounded_depth"] }
 serde_starlark = "0.1.13"
 strum = { version = "0.26.2", features = ["derive"] }
-syn = { version = "2.0.79", features = ["extra-traits", "fold", "full", "visit", "visit-mut"] }
+syn = { version = "2.0.85", features = ["extra-traits", "fold", "full", "visit", "visit-mut"] }
 termcolor = "1.0"
 toml = "0.8.4"
 toml_edit = { version = "0.20.5", features = ["serde"] }