Bump syn from 1.0.109 to 2.0.9 (#2397)

Bumps [syn](https://github.com/dtolnay/syn) from 1.0.109 to 2.0.9.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](https://github.com/dtolnay/syn/compare/1.0.109...2.0.9)

---
updated-dependencies:
- dependency-name: syn
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

cumulus/Cargo.lock

@@ -2098,7 +2098,7 @@ dependencies = [
  "proc-macro-crate",
  "proc-macro2",
  "quote",
- "syn 1.0.109",
+ "syn 2.0.9",
 ]
 
 [[package]]

cumulus/pallets/parachain-system/proc-macro/Cargo.toml

@@ -9,7 +9,7 @@ description = "Proc macros provided by the parachain-system pallet"
 proc-macro = true
 
 [dependencies]
-syn = "1.0.109"
+syn = "2.0.9"
 proc-macro2 = "1.0.52"
 quote = "1.0.26"
 proc-macro-crate = "1.3.1"