Link to the event/notification source directly

E.g: link to comments

app/views/mailers/notification/bundle_mailer/notification/event/_body.html.erb

@@ -1,7 +1,7 @@
 <% event = notification.source %>
 
 <h3 class="event__title">
-  <%= link_to event_notification_title(event), collection_card_url(notification.card.collection, notification.card) %>
+  <%= link_to event_notification_title(event), notification.source %>
 </h3>
 
 <p class="event__details">

app/views/mailers/notification/bundle_mailer/notification/mention/_body.html.erb

@@ -1,7 +1,7 @@
 <% mention = notification.source %>
 
 <h3 class="event__title">
-  <%= link_to "#{mention.mentioner.first_name} mentioned you", collection_card_url(notification.card.collection, notification.card) %>
+  <%= link_to "#{mention.mentioner.first_name} mentioned you", event.source %>
 </h3>
 
 <p class="event__details">

config/routes.rb

@@ -173,7 +173,7 @@ Rails.application.routes.draw do
   end
 
   resolve "Event" do |event, options|
-    polymorphic_path(event.target, options)
+    polymorphic_path(event.eventable, options)
   end
 
   get "up", to: "rails/health#show", as: :rails_health_check