Instruction for creating stage0 toolchain doesn't work

[champignoom]

https://github.com/rust-lang/rustc-dev-guide/blob/f1e637883fafeb83bdd5906ee7f467e4d35b7337/src/building/how-to-build-and-run.md?plain=1#L177

This instruction fails:

~/code/rust$ ./x.py build library
...
Build completed successfully in 0:04:44

~/code/rust$ rustup toolchain link stage0 build/host/stage0-sysroot/
error: not a directory: 'build/host/stage0-sysroot/bin'

~/code/rust$ find build -name bin
build/x86_64-unknown-linux-gnu/ci-llvm/bin
build/x86_64-unknown-linux-gnu/llvm/bin
build/x86_64-unknown-linux-gnu/llvm/build/bin
build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/bin
build/x86_64-unknown-linux-gnu/stage1/bin
build/x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/bin
build/x86_64-unknown-linux-gnu/stage0/bin
build/x86_64-unknown-linux-gnu/rustfmt/lib/rustlib/x86_64-unknown-linux-gnu/bin
build/x86_64-unknown-linux-gnu/rustfmt/bin

~/code/rust$ git rev-parse HEAD
9c843d9fa322596c7d525c78fa89731ecf7afbfe