build(deps): Update Rust crate syn to v2.0.84

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
syn	dependencies	patch	2.0.83 -> 2.0.84

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Release Notes

dtolnay/syn (syn)

### [`v2.0.84`](https://redirect.github.com/dtolnay/syn/compare/2.0.83...2.0.84) [Compare Source](https://redirect.github.com/dtolnay/syn/compare/2.0.83...2.0.84)

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