Bump syn from 1.0.3 to 1.0.4
Bump syn from 1.0.3 to 1.0.4

Bumps [syn](https://github.com/dtolnay/syn) from 1.0.3 to 1.0.4.
- [Release notes](https://github.com/dtolnay/syn/releases)
- [Commits](https://github.com/dtolnay/syn/compare/1.0.3...1.0.4)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
Alexendoo/utf,Alexendoo/utf,Alexendoo/utf,Alexendoo/utf