The `Borrowed` variant is no longer used. This commit removes it, along with the `as_results_cursor` method that produces it, and renames `as_results_cursor_mut` as `as_results_cursor`.
The `Borrowed` variant is no longer used. This commit removes it, along with the `as_results_cursor` method that produces it, and renames `as_results_cursor_mut` as `as_results_cursor`.