Fix #3863: "load" ispell after flyspell

Emacs loads both ispell and flyspell at startup, so to lazy load user
configuration to either package, we fool Emacs into thinking neither is
loaded yet.

However, this means we need a trigger to eventually "load" ispell, which
we didn't have until now, causing #3863.

modules/checkers/spell/config.el

@@ -173,6 +173,8 @@
                  #'flyspell-prog-mode))
 
     :config
+    (provide 'ispell) ; forcibly load ispell configs
+
     (setq flyspell-issue-welcome-flag nil
           ;; Significantly speeds up flyspell, which would otherwise print
           ;; messages for every word when checking the entire buffer