Add note about screenshot color space
Add note about screenshot color space

sindresorhus/pure,DFurnes/purer,depressiveRobot/pure-time,supercrabtree/pure,dmiedema/pure,bramkok/purist,joshuarubin/dotfiles,forivall/pure,joshuarubin/dotfiles,mafredri/pure,kgrz/pure,joshuarubin/dotfiles,jaredru/zsh-pure,boushley/pure,fvargas/pure,joshuarubin/dotfiles