fixes#8278
Emails are now sent to the customer when a partial refund is issued. I
referenced #7785 when doing this.
When a full refund happens the email the customer receives is clear
enough that they are getting a full refund. However I thought it would
be useful to add a new line in these new partial refund emails that
states exactly the value of the partial refund as it may not be that
clear.
Claudio Sanches
davidlenehan
Barry Kooij
Mike Jolley
shivapoudel