Document implicit hidden and non-publishable pages
Antora skips pages completely that begin with a
. (which is true for all files, in fact) and does not publish pages that begin with
_. Pages that begin with
_ are still cataloged so they can be used by the include directive (putting them in the partials directory is not mandatory).
Antora also skips files without a file extension. However, this behavior is being revisited. See #368.