patch 9.0.1001: classes are not documented or implemented yet

Problem:    Classes are not documented or implemented yet.
Solution:   Make the first steps at documenting Vim9 objects, classes and
            interfaces.  Make initial choices for the syntax.  Add a skeleton
            implementation.  Add "public" and "this" in the command table.
diff --git a/src/testdir/test_cmdmods.vim b/src/testdir/test_cmdmods.vim
index d5a4e93..323a78e 100644
--- a/src/testdir/test_cmdmods.vim
+++ b/src/testdir/test_cmdmods.vim
@@ -15,6 +15,16 @@
   lines = getline(top, bot)
   var mods = lines->map((_, v) => substitute(v, '.*"\(\k*\)".*', '\1', ''))
 
+  # Add the other commands that use ex_wrongmodifier.
+  mods->extend([
+                'endclass',
+                'endenum',
+                'endinterface',
+                'public',
+                'static',
+                'this',
+              ])
+
   # Check the lists are equal.  Convert them to a dict to get a clearer error
   # message.
   var cmds_dict = {}