Shpadoinkle git hash in docs, plus some typo fixes

This MR fixes #147 (closed) and #131 (closed). #147 (closed) was an issue simply because there wasn't a :haddock: attribute in the router docs.

#131 (closed) was fixed by pulling the latest shpadoinkle git hash on master, and creating a attribute for asciidoc to reference it. Furthermore, it uses the latest nixpkgs channel hash pulled directly from nix/chan.nix.

Unfortunately, this required a hack to be added to CI -- the way the docs get the current git commit hash on master is by directly getting it from .git/refs/heads/master. However, gitlab only pulls the branch just pushed when running continuous integration -- any branch that's not master will get a "file not found" error thrown. So, I forge .git/refs/heads/master by copying $CI_COMMIT_SHA to that file for every job in the pipeline that uses this default.nix.