Rollup merge of rust-lang#22866 - iKevinY:version-output-doc-fix, r=Manishearth

 The format of `rustc --version` was changed in rust-lang#21957; this PR updates TRPL accordingly.

Author: Manishearth

src/doc/trpl/installing-rust.md

@@ -70,10 +70,10 @@ If you've got Rust installed, you can open up a shell, and type this:
 $ rustc --version
 ```
 
-You should see some output that looks something like this:
+You should see the version number, commit hash, commit date and build date:
 
 ```bash
-rustc 1.0.0-nightly (f11f3e7ba 2015-01-04 20:02:14 +0000)
+rustc 1.0.0-nightly (f11f3e7ba 2015-01-04) (built 2015-01-06)
 ```
 
 If you did, Rust has been installed successfully! Congrats!