add link to contribution guidelines and IRC room

Author: pirate

src/libstd/lib.rs

@@ -96,9 +96,13 @@
 //!
 //! # Contributing changes to the documentation
 //!
-//! The source for this documentation can be found on [github](https://github.com/rust-lang/rust/tree/master/src/libstd).
-//! To contribute changes, you can search for nearby strings in github to find
-//! relevant files, then submit pull-requests with your suggested changes.
+//! Check out the rust contribution guidelines [here](https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md).
+//! The source for this documentation can be found on [Github](https://github.com/rust-lang/rust/tree/master/src/libstd).
+//! To contribute changes, make sure you read the guidelines first, then submit
+//! pull-requests for your suggested changes.
+//! 
+//! Contributions are appreciated! If you see a part of the docs that can be
+//! improved, submit a PR, or chat with us first on irc.mozilla.org #rust.
 //!
 //! # A Tour of The Rust Standard Library
 //!