cfulist_delete_data_with_free_fn was updated because of cfulist_set_free_function()

Now the doc explains better what happens with (if) a free function was previously set.

doc/libcfu.texi

@@ -522,7 +522,8 @@ cfulist_map().  The return value is used to build a new list.
 @deftypefun {void} cfulist_delete_data_with_free_fn (cfulist_t * @var{list}, void * @var{data}, cfulist_free_fn_t @var{ff})
 
  Deletes the entry in the list associated with value.  If ff is not NULL, it
- is called for value of the entry passed as its only argument.
+ is called for value of the entry passed as its only argument. If ff is not NULL,
+ it overrides any function set previously with cfulist_set_free_function().
  
 @end deftypefun