Problem:
- A window can only have one cursor, ranges selected by the cursor are typically
obtained by marks like ">" and "<", instead of calling get_cursor() twice.
- `vim.Range` is described as end-exclusive,
but the current `range.cursor()`/`range:to_cursor()` are end-inclusive.
- Conversion between `vim.Range` and mark-indexed range can be done by
`range.mark()`/`range:to_mark()`
Solution:
Remove `range.cursor()` and `range:to_cursor()`,
8d1233a144