Linkify LICENSE-* mentions

Author: est31

README.md

@@ -256,8 +256,8 @@ consensus and community norms, not impose more structure than necessary.
 
 This repository is currently in the process of being licensed under either of
 
-* Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
-* MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
+* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
+* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
 
 at your option. Some parts of the repository are already licensed according to those terms. For more see [RFC 2044](https://github.com/rust-lang/rfcs/pull/2044) and its [tracking issue](https://github.com/rust-lang/rust/issues/43461).