Payment period visible on subscription invoices

On invoices for recurring subscriptions, the payment period is now clearly displayed. This makes it visible on the invoice for which period the customer is paying, for example, from which start date to which end date the subscription or service covers.

This makes invoices clearer for clients and prevents confusion about exactly which month, period, or term is being billed. It also makes it easier for coaches and studios to quickly answer questions about subscription fees and billing periods.