Merge pull request #532 from brson/docs-rs

Add docs.rs link to docs page

Author: steveklabnik

en-US/documentation.md

@@ -42,6 +42,8 @@ for learning Rust.
 [Standard Library API Reference][api]. Documentation for the
 standard library.
 
+[docs.rs]. Documentation for all crates published to [crates.io].
+
 [The Rust Reference][ref]. While Rust does not have a
 specification, the reference tries to describe its working in
 detail. It tends to be out of date.
@@ -64,6 +66,8 @@ the errors produced by the Rust compiler.
 [cargo]: http://doc.crates.io/guide.html
 [err]: https://doc.rust-lang.org/error-index.html
 [release_notes]: https://github.com/rust-lang/rust/blob/stable/RELEASES.md
+[docs.rs]: https://docs.rs
+[crates.io]: https://crates.io
 
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