Fix broken link to Rust FAQ

It seems the Rust FAQ was dropped with website redesign. This question doesn't seem to be answered on any current resource, but the old website is still available.

Author: intgr

src/necessities.md

@@ -56,7 +56,7 @@ over licensing options.
 
 [MIT]: https://github.com/rust-lang/rust/blob/master/LICENSE-MIT
 [Apache 2.0]: https://github.com/rust-lang/rust/blob/master/LICENSE-APACHE
-[Rust FAQ]: https://www.rust-lang.org/en-US/faq.html#why-a-dual-mit-asl2-license
+[Rust FAQ]: https://prev.rust-lang.org/en-US/faq.html#why-a-dual-mit-asl2-license
 
 To apply the Rust license to your project, define the `license` field in your
 `Cargo.toml` as: