that line in the nimdoc.cfg changed in v1.4.2. pacman doesn't overwrite config files when upgrading: [(arch wiki)](https://wiki.archlinux.org/index.php/Pacman/Pacnew_and_Pacsave) I expect you have a .pacnew file with the upgrade that you need to move over. I recommend pacmatic for upgrading, it prompts you about config file changes
i know it goes against the arch way, but i also recommend using choosenim (in the aur) to maintain and install nim versions, it'll let you switch easily between stable/devel should that interest you.
