Use `bool` instead of `PartiolOrd` as return value of the comparison closure in `{slice,Iteraotr}::is_sorted_by` Changes the function signature of the closure given to `{slice,Iteraotr}::is_sorted_by` to return a `bool` instead of a `PartiolOrd` as suggested by the libs-api team here: https://github.com/rust-lang/rust/issues/53485#issuecomment-1766411980. This means these functions now return true if the closure returns true for all the pairs of values.