patch 8.2.2840: Vim9: member operation not fully tested

Problem:    Vim9: member operation not fully tested.
Solution:   Add a few tests.
diff --git a/src/version.c b/src/version.c
index 36422c1..d2ffe6f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2840,
+/**/
     2839,
 /**/
     2838,