_file output directory

Analogous to the _raw directory, but contains an HTML page that displays the contents of the file inside of it.

As such, unlike in the _raw directory which just contains the file raw, the page can also contain useful metadata about the file, such as:

If the file has a corresponding \H file argument section, and when using -S, --split-headers, then the content of the corresponding section are shown. Otherwise, only the file is shown.