docs: Fix Vim documentation for `toggle_relative_line_numbers` (#46152)

As reported in
https://github.com/zed-industries/zed/pull/44749#issuecomment-3712881279

Release Notes:

- N/A
9fcb36a87fFinn Evers committed on 1/6/2026, 11:59:00 AM· committed by GitHubparentbbb3d51
1 file changedLine totals unavailable