Problem: fnamemodify() treats ".." and "../" differently.
Solution: Expand ".." properly like how "/.." is treated in 8.2.3388.
(zeertzjq)
closes: vim/vim#152181ee7420460
Problem: fnamemodify('path/..', ':p') differs from using 'path/../'.
Solution: Include the "/.." in the directory name. (closesvim/vim#8808)
4eaef9979f
Co-authored-by: Bram Moolenaar <Bram@vim.org>