patch 8.2.2303: Vim9: backtick expansion doesn't work for :foldopen

Problem:    Vim9: backtick expansion doesn't work for :foldopen.
Solution:   Do recognize backtick expansion. (closes #7621)
diff --git a/src/version.c b/src/version.c
index e7c3ee0..a2553fc 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2303,
+/**/
     2302,
 /**/
     2301,