INSTALLATION: Link to getting-started
INSTALLATION: Link to getting-started

The previous installing chapter has been subsumed into this chapter:
https://github.com/rust-lang/rust/commit/2f4fbb2bf5bceb2816925789c7d9534debbcd2b0

exercism/xrust,petertseng/exercism-rust,sacherjj/rust,exercism/xrust,sacherjj/rust,sacherjj/rust,petertseng/exercism-rust,petertseng/exercism-rust