(spell-filter): Fix :type.

diff --git a/lisp/textmodes/spell.el b/lisp/textmodes/spell.el
index bd58262963bbb083b9be7eefc16a65346d44dcad..e8fe420a842562993e418a126fb4100cce21f1a3 100644 (file)
--- a/lisp/textmodes/spell.el
+++ b/lisp/textmodes/spell.el
@@ -46,7 +46,7 @@
   "*Filter function to process text before passing it to spell program.
 This function might remove text-processor commands.
 nil means don't alter the text before checking it."
-  :type 'function
+  :type '(choice (const nil) function)
   :group 'spell)
 
 ;;;###autoload