l command uses different escape format than GNU


  Rust (incorrect format)
```
  $ echo "cÃ🧰y" | cargo run --quiet -- -e 'l'
  # Output: c\u00C3\U0001F9F0y$
  # (Uses \uXXXX and \UXXXXXXXX Unicode escape format)
  # Exit code: 0
```
  GNU (correct format)
```
  $ echo "cÃ🧰y" | /usr/bin/sed -e 'l'
  # Output: c\303\203\360\237\247\260y$
  # (Uses \XXX octal escape format)
  # Exit code: 0
```

  Bug Found by Fuzzer