Fix typos in access Lexicon (#16689)

### Why is it needed?
Avoid potential php error for undefined var

### Related issue(s)/PR(s)
Resolves #16679

core/lexicon/en/access.inc.php

@@ -175,6 +175,6 @@
 $_lang['user_group_namespace_authority_desc'] = 'The minimum Role that will have access to the Permissions in the selected Policy. Roles with stronger Authority (lower numbers) will inherit this access as well. Most situations can leave this at "Member".';
 $_lang['user_group_namespace_policy_desc'] = 'The Policy to apply to this Namespace for this User Group. This will grant all Users in this User Group with the selected minimum Role all the Permissions in the Policy.';
 
-// Renamed, deprecated as of 3.0.4, remove in 3.1.0
-$_lang['access_rgroup_remove'] = $lang['access_resourcegroup_remove'];
-$_lang['access_rgroup_update'] = $lang['access_resourcegroup_update'];
+// Renamed, deprecated as of 3.0.4, remove in 3.2.0
+$_lang['access_rgroup_remove'] = $_lang['access_resourcegroup_remove'];
+$_lang['access_rgroup_update'] = $_lang['access_resourcegroup_update'];