patch 9.0.1559: function argument types not always checked

Problem:    Function argument types not always checked and using v:none may
            cause an error.
Solution:   Check argument types once the function type is known.  Do not give
            an error for using v:none as an argument. (closes #12200)

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1559,
 /**/
     1558,
 /**/