patch 8.2.2393: Vim9: error message when script line starts with "[{"

Problem:    Vim9: error message when script line starts with "[{".
Solution:   Do not give an error for checking for end of list.
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index 957671c..9dadf1e 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -815,6 +815,12 @@
       # comment 6
   END
   assert_equal(['# comment 1', 'two', '# comment 3', '', 'five', '# comment 6'], lines)
+
+  lines =<< trim END
+    [{
+      a: 0}]->string()->assert_equal("[{'a': 0}]")
+  END
+  CheckDefAndScriptSuccess(lines)
 enddef
 
 if has('channel')