Customize Text: New custom role permission

This change may require updates to existing custom role permissions.

While we're still finishing up the last few areas for the Customize Text tool, we've made one important change: there's now an explicit permission to grant/deny access to Customize Text in custom author roles.

If you've already been using Customize Text and have custom author roles in place, we suggest you review the custom role options in the Tools Permissions section of those roles and decide who should have access to Update Customize Text.

As always, our standard Editor and Writer roles have permission to update Customize Text.