排序: 使算法能够对任何可比较的项进行排序,而不仅仅是 int 类型的项

Many of our `sorts/` implementations are written and tested only against `list[int]`, even though most comparison sorts work for **any** items that support `<`. This issue collects the small, well-scoped changes that make them correctly typed and tested for the general case — a good batch of beginner-friendly PRs for Hacktoberfest.