Use bat for fzf preview

Hi! Thanks for this great doc!
Do you know that you could also use [bat](https://github.com/sharkdp/bat) (`cat` with colors) in your `fzf` preview!

```sh
fzf --preview 'bat --style=numbers --color=always {}'

# I use it with vim to find and open a file on enter, aliased as `vifz`
vim $(fzf --preview 'bat --style=numbers --color=always {} | head -500')
```

Best