chore: upgrade syn to 3.0.3

[tisonkun]

Summary

• upgrade the workspace syn dependency from 2.0.117 to 3.0.3
• refresh Cargo.lock so stacksafe-macro resolves syn 3.x

Testing

• cargo fmt --all -- --check
• cargo clippy --all-targets --all-features -- --deny warnings
• cargo test -- --nocapture
• cargo build --workspace --all-targets --release
• cargo +1.85.0 build --workspace --all-targets
• cargo +1.85.0 test -- --nocapture
• taplo check
• typos
• hawkeye check

[tisonkun]

@andylokandy I'm going to rolling release all our crates depending on syn 2 which is now syn 3.