'ship stage 1 artifacts' -> 'ship stage 2 compiler'

This is hopefully less confusing.

Author: jyn514

src/building/bootstrapping.md

@@ -172,7 +172,7 @@ Keep in mind this diagram is a simplification, i.e. `rustdoc` can be built at
 different stages, the process is a bit different when passing flags such as
 `--keep-stage`, or if there are non-host targets.
 
-The stage 1 artifacts are what is shipped to end-users, including `stage2/bin/rustc`.
+The stage 2 compiler is what is shipped to end-users.
 
 ### Stages and libstd