Update README.mkd
Update README.mkd

My rational for this is:
 1. Most linux desktop users are using some kind of debian/ubuntu/mint, so why not have them catered for primarily?
 2. the bash instructions work for everyone who has bash. Last time I checked, that was 99% of the linux community.
joshuarubin/dotfiles,joshuarubin/dotfiles,reinhrst/zsh-autosuggestions,jirutka/zsh-autosuggestions,joshuarubin/dotfiles,zsh-users/zsh-autosuggestions,zsh-users/zsh-autosuggestions,jrtc27/zsh-autosuggestions,joshuarubin/dotfiles,lodestone/zsh-autosuggestions,a-x-/zsh-autosuggestions,tarruda/zsh-autosuggestions,ascenator/zsh-autosuggestions