patch 8.2.5169: nested :source may use NULL pointer

Problem:    Nested :source may use NULL pointer.
Solution:   Do not use the NULL pointer.
diff --git a/src/version.c b/src/version.c
index 5ac1cb9..4a7e83f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -736,6 +736,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    5169,
+/**/
     5168,
 /**/
     5167,