Remove "Known problems" section for `clippy::redundant_closure` since it was fixed by [this PR](https://github.com/rust-lang/rust-clippy/pull/4008) We can see this by running examples from [the issue](https://github.com/rust-lang/rust-clippy/issues/1439), for ex. [this one](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=6562527b4c3f6dcebb3c43718341af98) changelog: none