patch 9.0.1336: functions without arguments are not always declared properly

Problem:    Functions without arguments are not always declared properly.
Solution:   Use "(void)" instead of "()". (Yegappan Lakshmanan, closes #12031)

src/misc1.c

@@ -1313,7 +1313,7 @@ free_users(void)
 
 #if defined(MSWIN) || defined(PROTO)
 /*
- * Initilize $VIM and $VIMRUNTIME when 'enc' is updated.
+ * Initialize $VIM and $VIMRUNTIME when 'enc' is updated.
  */
     void
 init_vimdir(void)
@@ -2777,7 +2777,7 @@ restore_v_event(dict_T *v_event, save_v_event_T *sve)
  * Fires a ModeChanged autocmd event if appropriate.
  */
     void
-may_trigger_modechanged()
+may_trigger_modechanged(void)
 {
 #ifdef FEAT_EVAL
     dict_T	    *v_event;