Rule 3 has an error in the first example given.
Please review the PR Fix pig-latin instructions by 0xwetzo · Pull Request #2000 · exercism/rust · GitHub
It was already reported by another user on Python ([Pig Latin] Typo in the instructions) and fixed in the global specs (problem-specifications/exercises/pig-latin/instructions.md at main · exercism/problem-specifications · GitHub) but Rust is not sync so the issue is still there.