vimrc: improve warning for css files with scss/sass present
vimrc: improve warning for css files with scss/sass present

scorpiovn/dotfiles,blueyed/dotfiles,scorpiovn/dotfiles,blueyed/dotfiles,scorpiovn/dotfiles,blueyed/dotfiles,blueyed/dotfiles,scorpiovn/dotfiles,scorpiovn/dotfiles,blueyed/dotfiles