## Summary
Attempt at a small improvement to two `perflint` rules using the new
type inference capabilities to only flag `PERF401` and `PERF402` for
values we infer to be lists. This makes the rule more conservative, as
it only flags values that we _know_ to be lists, but it's overall a
desirable change, as it favors false negatives over false positives for
a "nice-to-have" rule.
Closes https://github.com/astral-sh/ruff/issues/6995.
## Test Plan
Add non-list value cases and make sure all old cases are still caught.
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