another spell checker

   * checks the internal anchors and links using Nanoc

 * [codespell][] checks for typos in program source code, but also

   happens to handle Markdown nicely, it can also apply corrections

   for errors it finds

   for errors it finds, an alternative is [typos](https://github.com/crate-ci/typos), written in Rust

 * [Danger systems](https://danger.systems/ruby/) has a bunch of plugins which could be used to

   check documentation ([lefthook](https://github.com/evilmartians/lefthook), [precious](https://github.com/houseabsolute/precious), and

   [pre-commit](https://pre-commit.com/) are similar wrappers)