Jack's contribution is below the ~15 line threshold that is required for
projects that are distributed via GNU ELPA (denote will be one of them
in the near future).
Contributions exceeding that limit require that the author assigns
copyright to the Free Software Foundation.
There is no need to limit it to the denote-directory. We ultimately
want to fontify all Denote-style file names, not just the notes created
by Denote.
For example, I have been recording all my longer-term storage using such
a naming scheme: this mode gives me the extra faces for .pdf, .mp3, and
other files.
Users of Denote may want this for attachments.
The upside of having this as a buffer-local mode is that the user can
write a wrapper function that applies the mode only in a given
directory (like we were doing before).
Thanks to Ypot for suggesting a kernel of this idea in issue 1 over at
the GitHub mirror: <https://github.com/protesilaos/denote/issues/1>.