rustc-guide has moved

Author: mark-i-m

src/doc/index.md

@@ -107,6 +107,6 @@ Rust. It's also sometimes called "the 'nomicon."
 
 ## The `rustc` Contribution Guide
 
-[The `rustc` Guide](https://rust-lang-nursery.github.io/rustc-guide/) documents how
+[The `rustc` Guide](https://rust-lang.github.io/rustc-guide/) documents how
 the compiler works and how to contribute to it. This is useful if you want to build
 or modify the Rust compiler from source (e.g. to target something non-standard).