Fix heading order on total by site table (#524)

Thanks to Ileri for spotting!

Author: frankieroberto

app/views/home/_by-site.html

@@ -9,10 +9,10 @@
         Today
       </th>
       <th role="columnheader" class="nhsuk-table__header--numeric" scope="col">
-        {{ (monthToday | monthName) }} to date
+        Past 7 days
       </th>
       <th role="columnheader" class="nhsuk-table__header--numeric" scope="col">
-        Past 7 days
+        {{ (monthToday | monthName) }} to date
       </th>
       <th role="columnheader" class="nhsuk-table__header--numeric" scope="col">
         Total