Error
{#
I'd like to use ``build.error|urlize`` here, so we can have nice links.
However, this is not possible because we are using `data-bind="text: error"`
which means that Knockout.js will use the `.error` attribute to fill
the content of this tag dynamically.
#}
could not determine a constructor for the tag 'tag:yaml.org,2002:python/name:pymdownx.headeranchor.uslugify'
in "/home/docs/checkouts/readthedocs.org/user_builds/nwjs/checkouts/latest/mkdocs.yml", line 5, column 18