## Summary
Part of #18972
This PR makes [for-loop-writes
(FURB122)](https://docs.astral.sh/ruff/rules/for-loop-writes/#for-loop-writes-furb122)'s
example error out-of-the-box. I also had to re-name the second case's
variables to get both to raise at the same time, I suspect because of
limitations in ruff's current semantic model. New names subject to
bikeshedding, I just went with the least effort `_b` for binary suffix.
[Old example](https://play.ruff.rs/19e8e47a-8058-4013-aef5-e9b5eab65962)
```py
with Path("file").open("w") as f:
for line in lines:
f.write(line)
with Path("file").open("wb") as f:
for line in lines:
f.write(line.encode())
```
[New example](https://play.ruff.rs/e96b00e5-3c63-47c3-996d-dace420dd711)
```py
from pathlib import Path
with Path("file").open("w") as f:
for line in lines:
f.write(line)
with Path("file").open("wb") as f_b:
for line_b in lines_b:
f_b.write(line_b.encode())
```
The "Use instead" section was also modified similarly.
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected