Bump unicode-ident from 1.0.12 to 1.0.13 in /src/rust

Bumps [unicode-ident](https://github.com/dtolnay/unicode-ident) from 1.0.12 to 1.0.13.
- [Release notes](https://github.com/dtolnay/unicode-ident/releases)
- [Commits](dtolnay/unicode-ident@1.0.12...1.0.13)

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

Signed-off-by: dependabot[bot] <[email protected]>