Rename ‘this year’

Make it clear that this section is about what you’ve used, ie your usage

Click ‘breakdown’ to see how the maths is done, and what time period it
covers.

app/templates/views/usage.html

@@ -3,7 +3,7 @@
 {% extends "withnav_template.html" %}
 
 {% block page_title %}
-  Billing – GOV.UK Notify
+  Usage – GOV.UK Notify
 {% endblock %}
 
 {% block maincolumn_content %}