Bump syn from 1.0.101 to 1.0.102 in /src/rust (#7677)

Bumps [syn](https://github.com/dtolnay/syn) from 1.0.101 to 1.0.102.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](dtolnay/syn@1.0.101...1.0.102)

---
updated-dependencies:
- dependency-name: syn
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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