In guide.md: "toolchain-resolution-debug" should use underscores

[yikelu]

I was following along with the guide and had one problem:

bash:~/dev/bazel-nix-ex$ bazel --version
bazel 5.4.1- (@non-git)
bash:~/dev/bazel-nix-ex$ bazel build //src:hello-world --toolchain-resolution-debug '.*'
ERROR: --toolchain-resolution-debug :: Unrecognized option: --toolchain-resolution-debug

Switching the dashes to underscores fixes this:

~/dev/bazel-nix-ex$ bazel build //src:hello-world --toolchain_resolution_debug '.*'

I didn't think a fork+PR was appropriate for this size of problem. Cheers.

[benradf]

Thanks for reporting this @yikelu. I've now fixed it.