patch 8.2.4009: reading one byte beyond the end of the line

Problem:    Reading one byte beyond the end of the line.
Solution:   Check for NUL byte first.
diff --git a/src/version.c b/src/version.c
index 48a1c98..6b7a915 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4009,
+/**/
     4008,
 /**/
     4007,