Lint simple expressions in `manual_filter_map`, `manual_find_map`
changelog: Lint simple expressions in [`manual_filter_map`], [`manual_find_map`]
The current comparison rules out `.find(|a| a.is_some()).map(|b| b.unwrap())` because `a` being a reference can effect more complicated expressions, this adds a simple check for that case and adds the necessary derefs
There's some overlap with `option_filter_map` so `lint_filter_some_map_unwrap` now returns a `bool` to indicate it linted