consult-denote

Integrate the `denote' and `consult' packages:

- [Denote](https://github.com/protesilaos/denote) : A file-naming
  scheme to easily retrieve files of any type.  Useful for note-taking
  and long-term storage files.
- [Consult](https://github.com/minad/consult): Enhanced interactivity
  for the standard Emacs minibuffer, such as a preview mechanism for
  buffers and an asynchronous grep/find.

The purpose of `consult-denote` is as follows:

1. **Upgrade all the minibuffer prompts of Denote:** For the time
   being, this means that we show a preview of the file to-be-linked
   or to-be-opened.  Simply enable the `consult-denote-mode'.  The
   prompts all use the same patterns as core Denote and *will never
   deviate from this paradigm*, such as to prettify titles or whatnot
   (that is an expensive operation that slows down Emacs).

2. **Easy search for the `denote-directory`:** Implement
   Consult-powered Grep and Find commands which operate on the
   `denote-directory` regardless of where they are called from.  See
   the commands `consult-denote-grep` and `consult-denote-find'.
   Customise which command they call by modifying the user options
   `consult-denote-grep-command` and `consult-denote-find-command`.

3. **Include Denote "sources" for `consult-buffer':** This is also
   part of the `consult-denote-mode'.  It adds new headings/groups to
   the interface of the `consult-buffer` command.  Those lists (i) the
   buffers that visit Denote files, (ii) the subdirectories of the
   `denote-directory', and (iii) the silos listed in the value of the
   user option `denote-silo-directories' (for those who opt in
   to that extension).

In the future we may use other features of Consult, based on user
feedback.