TODOs having to do with the technical/meta aspects of doc, rather than the
documentation itself

Definites:
    * Make type-graph.txt support more fine-grained metainfo, perhaps
        using a TOML-like syntax, and use this for grouping
    * More metadata for Language/ and for routines
    * Figure out a way to cache and update the documentation
        registry, and when to or not to regenerate individual pages.
    * Create a .tar.gz to satisfy the index page's claim that
        "you can also download an offline HTML ... copy"
Maybes:
    * Add "Formalities" page
    * Make links automatically be formatted super pretty, as with "language>intro"
    * A PDF version of the documentation
