Make page_title translateable.

biscuit/apps/alsijil/templates/alsijil/register_absence.html

@@ -14,7 +14,7 @@
 
 {% block bootstrap4_title %}{% blocktrans%}Manage absence{% endblocktrans %} - {{ block.super }}{% endblock %}
 
-{% block page_title %}Manage absences{% endblock %}
+{% block page_title %}{% blocktrans %}Manage absence{% endblocktrans %}{% endblock %}
 
 {% block content %}