I18n 'could not be saved'

app/views/activities/_form.html.erb

 <%= form_for([@group, activity]) do |f| %>
   <% if activity.errors.any? %>
     <div id="error_explanation">
-      <h2><%= pluralize(activity.errors.count, "error") %> prohibited this activity from being saved:</h2>
+      <h2>
+        <%= I18n.t(:could_not_be_saved, errorcount: I18n.t(:error, count: activity.errors.count), class: I18n.t('activities.singular')) %>
+      </h2>
 
       <ul>
       <% activity.errors.full_messages.each do |message| %>

config/locales/aardbei_en.yml

 
   invalid_csrf: "You submitted an invalid request! If you got here after clicking a link, it's possible that someone is doing something nasty!"
 
+  could_not_be_saved: "%{errorcount} prevented this %{class} from being saved:"
+
+  error:
+    zero: "no errors"
+    one: "an error"
+    other: "%{count} errors"
+
   activerecord:
     models:
       person:

config/locales/aardbei_nl.yml

   value_required: "Een verplichte vraag was leeg."
 
   invalid_csrf: "Ongeldig authenticiteitstoken! Als je hier terecht bent gekomen na het klikken op een link is het mogelijk dat iemand iets naars probeerde!"
+
+  could_not_be_saved: "Door %{errorcount} kon deze %{class} niet worden opgeslagen:"
+
+  error:
+    zero: "geen fouten"
+    one: "een fout"
+    other: "%{count} fouten"