patch 8.2.1968: Vim9: has() assumes a feature does not change dynamically

Problem:    Vim9: has() assumes a feature does not change dynamically.
Solution:   Check whether a feature may change dynamically. (closes #7265)
diff --git a/src/version.c b/src/version.c
index fe89862..40f3851 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1968,
+/**/
     1967,
 /**/
     1966,