Shows activation and cancellation messages after visiting an activation or cancellation link.
It is automatically included on the Newsletter Subscription page that can be generated under Subscription Activation Page in Newsletters > Settings.
Attributes:
‘activation_message’ : Shown on activation, default: ‘Thank you, your newsletter subscription has been activated.’.
‘cancellation_message’ : Shown after unsubscribing, default: ‘Thank you, your newsletter subscription has been cancelled.’.