Missing clang for fast compiles (Arch Linux)

[pheki]

In the setup page (getting-started/setup) the only dependency specified to run with the config_fast_builds is lld, but clang is also required...

Maybe it should be sudo pacman -S lld clang? (I can open a PR to add that)

I'm also not sure if this affects Ubuntu and other distros (unless they install clang with lld, I'd be inclined to believe so)

And thanks a lot for this awesome crate 😄