ruff: Enable B023 Function definition does not bind loop variable.

Python’s loop scoping is misdesigned, resulting in a very common
gotcha for functions that close over loop variables [1].  The general
problem is so bad that even the Go developers plan to break
compatibility in order to fix the same design mistake in their
language [2].

Enable the Ruff rule function-uses-loop-variable (B023) [3], which
conservatively prohibits functions from binding loop variables at all.

[1] https://docs.python-guide.org/writing/gotchas/#late-binding-closures
[2] https://go.dev/s/loopvar-design
[3] https://beta.ruff.rs/docs/rules/function-uses-loop-variable/

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zilencer/management/commands/queue_rate.py

@@ -70,10 +70,7 @@ class Command(BaseCommand):
                         lambda: queue_json_publish(queue_name, {}),
                         number=count,
                     )
-                    duration = timeit(
-                        lambda: worker.start(),
-                        number=1,
-                    )
+                    duration = timeit(worker.start, number=1)
                     print(f"    {i}/{reps}: {count}/{duration}s = {count / duration}/s")
                     total_time += duration
                     writer.writerow(