patch 8.2.3556: filler lines are incorrect for other window in diff mode

Problem:    Filler lines are incorrect for other window in diff mode after
            making a change.
Solution:   Copy filler lines from the current window. (closes #8809)

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3556,
 /**/
     3555,
 /**/