patch 8.2.1561: using NULL pointers in fold code

Problem:    Using NULL pointers in fold code.
Solution:   Avoid using a NULL pointer. (Dominique Pellé, closes #6831,
            closes #6831)

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1561,
 /**/
     1560,
 /**/