- Always open the right window to the right, regardless of 'splitright'
setting, ensuring the left window is always leftmost.
- Use `vim.fn.systemlist` for diffr output to avoid manual splitting.
- Add a test to verify window layout consistency with 'splitright' and
'nosplitright' options.
- Escape quotes in git difftool example properly.
Signed-off-by: Tomas Slusny <slusnucky@gmail.com>