anchor.diff:  
   (define-command update-hostlists (&optional (blocker-mode (find-submode 'nyxt/blocker-mode:blocker-mode (current-buffer))))
     "Forces update for all the hostlists of `blocker-mode'."
  -  (load-hostlists blocker-mode :force-update-p t)
  -  (echo "Hostlists updating..."))
  +  (load-hostlists blocker-mode :force-update-p t))
  
positive.code: 
  ;; TODO: Add convenient interface to block hosts depending on the current URL.
  
  (define-class hostlist (files:data-file nyxt-file)
    ((url
      (quri:uri "")
      :type quri:uri
      :documentation "URL where to download the list from.  If empty, no attempt
  will be made at updating it.")
     (url-body
      ""
      :type string)
     (hosts
      '()
      :type (or (cons string *) null)
      :documentation "List of hosts to ignore.
  This is useful to reference hosts manually instead of via `url'.")
     (last-update
      0
      :type integer)
     (update-interval
      (* 60 60 24)
      :type integer
      :documentation "If URL is provided, update the list after this amount of
  seconds.")
     (force-update-p
      nil
      :type boolean
      :export nil
      :documentation "When non-nil, reload the list from its URL, by-passing local files if any.
  It's automatically reset by `load-hostlists'."))
    (:export-class-name-p t)
    (:export-accessor-names-p t)
    (:accessor-name-transformer (class*:make-name-transformer name))
  
negative.code: (defun load-hostlists (blocker-mode &key force-update-p)
    "Load BLOCKER-MODE's hostlists into `blocked-hosts' (in the background)."
    (clrhash (blocked-hosts blocker-mode))
    (dolist (hostlist (hostlists blocker-mode))
      ;; TODO: Allow running in the background, but warning, it could leak
      ;; personal information to undesired third-party.
      (dolist (host (or (hosts hostlist)
                        (let ((path (files:expand hostlist)))
                          (unless (uiop:file-exists-p path)
                            (echo "Updating hostlist ~s..." path))
                          (files:content hostlist
                                         :force-update force-update-p))))
        (setf (gethash host (blocked-hosts blocker-mode)) host))))
  
  (defmethod blocklisted-host-p ((mode blocker-mode) host)
    "Return non-nil of HOST if found in the hostlists of MODE.
  