patch 8.2.0724: Vim9: appending to buffer/window/tab variable not tested

Problem:    Vim9: appending to buffer/window/tab variable not tested
Solution:   Add a test.
diff --git a/src/version.c b/src/version.c
index 3084d9b..38da744 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    724,
+/**/
     723,
 /**/
     722,