Upgrade syn

Summary: For this change: dtolnay/syn#1690

Reviewed By: dtolnay

Differential Revision: D63712744

fbshipit-source-id: e6a7e0c58b8dcfd4f5b7e5114270c47e3e186ee9

Author: stepancheg

Cargo.lock

@@ -32,7 +32,7 @@ serde = { version = "1.0.185", features = ["derive", "rc"] }
 serde_json = { version = "1.0.100", features = ["float_roundtrip", "unbounded_depth"] }
 serde_starlark = "0.1.13"
 strum = { version = "0.26.2", features = ["derive"] }
-syn = { version = "2.0.38", features = ["extra-traits", "fold", "full", "visit", "visit-mut"] }
+syn = { version = "2.0.79", features = ["extra-traits", "fold", "full", "visit", "visit-mut"] }
 termcolor = "1.0"
 toml = "0.8.4"
 toml_edit = { version = "0.20.5", features = ["serde"] }