Fix #3827: void-variable flyspell-delayed-commands

This occurs in org-compat.el:

  (eval-after-load "flyspell"
    '(add-to-list 'flyspell-delayed-commands 'org-self-insert-command))

By not using a package symbol, this code runs whenever any file named
flyspell.el is loaded. Guess what one of the :checkers spell module's
autoloads files is named? flyspell.el

modules/checkers/spell/autoload/+flyspell.el

@@ -1,4 +1,4 @@
-;;; checkers/spell/autoload/flyspell.el -*- lexical-binding: t; -*-
+;;; checkers/spell/autoload/+flyspell.el -*- lexical-binding: t; -*-
 ;;;###if (featurep! +flyspell)
 
 ;;;###autodef

modules/checkers/spell/autoload/+spell-fu.el

@@ -1,4 +1,4 @@
-;;; checkers/spell/autoload/spell-fu.el -*- lexical-binding: t; -*-
+;;; checkers/spell/autoload/+spell-fu.el -*- lexical-binding: t; -*-
 ;;;###if (not (featurep! +flyspell))
 
 (defun +spell--correct (replace poss word orig-pt start end)
@@ -50,10 +50,10 @@
 (defun +spell/correct ()
   "Correct spelling of word at point."
   (interactive)
-  ;; We fake awareness for our personal dictionary by stopping short if spell-fu
-  ;; hasn't highlighted the current word. This is necessary because
-  ;; ispell/aspell struggles to find our `ispell-personal-dictionary' if it's
-  ;; not in $HOME.
+  ;; HACK Fake awareness for our personal dictionary by stopping short if
+  ;;      spell-fu hasn't highlighted the current word. This is necessary
+  ;;      because ispell/aspell struggles to find our
+  ;;      `ispell-personal-dictionary' if it's not in $HOME.
   (unless (memq 'spell-fu-incorrect-face (face-at-point nil t))
     (user-error "%S is correct" (thing-at-point 'word t)))
   (ispell-set-spellchecker-params)