Change page <title> on check page

It was no longer accurate.

app/templates/views/check.html

@@ -10,7 +10,7 @@
 {% from "components/message-count-label.html" import message_count_label %}
 
 {% block page_title %}
-  {{ page_heading if errors else "Check and confirm" }} – GOV.UK Notify
+  {{ "Error" if errors else "Check and confirm" }} – GOV.UK Notify
 {% endblock %}
 
 {% block maincolumn_content %}