patch 8.2.4080: not sufficient test coverage for xxd

Problem:    Not sufficient test coverage for xxd.
Solution:   Add a few more test cases. (Erki Auerswald, closes #9515)
diff --git a/src/version.c b/src/version.c
index 8396874..0089232 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4080,
+/**/
     4079,
 /**/
     4078,