Change how notes are handled for WooCommerce order emails

WooCommerce allows a note to be added to an order. However, when a note is added to an account, an email is sent. My customers are getting too many emails and all the notes are not all in one place for them since they are not added to the order "shipped" email. So... I need any customer note be added to the "shipped" email - and not go out as a separate email. This is implemented on my current site very well - but it was not added as a plugin and so is not portable to my new WooCommerce site. You can dig out the code from the current site and make it a plugin. Or design one of your own to meet these requirements: - When a note is added to an order - an email is NOT sent, rather is just added as an addendum to the "Shipped" email. So that when an order is shipped, the customer gets that email with the usual "shipped" language AND the note. - This must be added such that WordPress, WooCommerce and the theme can all be updated without losing this functionality. - If it can be added a a plugin, (and there for easy to port it to a new site when needed) so much the better.