patch 8.2.0519: Vim9: return type not properly checked

Problem:    Vim9: return type not properly checked.
Solution:   Check type properly, also at runtime.
diff --git a/src/version.c b/src/version.c
index f420990..6e9f006 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    519,
+/**/
     518,
 /**/
     517,