Fix vim selection to include entire range (#2787)

Update vim mode to have vim selection and editor selections match.
Before this we had to adjust between vim selections and real selections
when making changes; now we have to adjust when making selections.

Release Notes:

- vim: Ensure editor selection matches the vim selection
([#1796](https://github.com/zed-industries/community/issues/1796)).
- vim: Fix `s` in visual line mode
- vim: Add `o` and `shift-o` to toggle direction of visual selection
- vim: Fix `v` and `shift-v` to toggle back to normal mode
- vim: Fix block selections like `vi}` to contain correct whitespace