Auto merge of #29966 - MatthiasKauer:master, r=steveklabnik

This commit changes the location of the rust docs.
024aa9a
Clicking the contribution link on the front page therefore becomes a 'not found' error.

Author: bors

src/doc/book/README.md

@@ -42,7 +42,6 @@ Copious cross-linking connects these parts together.
 ### Contributing
 
 The source files from which this book is generated can be found on
-[GitHub][trpl].
-
-[trpl]: https://github.com/rust-lang/rust/tree/master/src/doc/trpl
+[GitHub][book].
 
+[book]: https://github.com/rust-lang/rust/tree/master/src/doc/book