Fix link

Author: nikomatsakis

_posts/2015-05-15-Rust-1.0.md

@@ -319,7 +319,7 @@ whom contributed changes since our previous release (the
 [crates.io]: https://crates.io/
 [cargo]: http://blog.rust-lang.org/2014/11/20/Cargo.html
 [relnotes]: https://github.com/rust-lang/rust/blob/master/RELEASES.md#version-100-may-2015
-[caveats]: ???
+[caveats]: https://github.com/rust-lang/rfcs/pull/1122
 [book]: http://doc.rust-lang.org/1.0.0-beta.5/book/getting-started.html
 [ffi]: http://blog.rust-lang.org/2015/04/24/Rust-Once-Run-Everywhere.html
 [AUTHORS]: https://github.com/rust-lang/rust/blob/master/AUTHORS.txt