message: Fix bug in generated XML
diff: @@ -154,7 +154,7 @@ Generated by fpp-to-xml
  </commands>
  <events>
  - <event id="0x0" name="SEVERITY_FILTER_STATE" severity="ACTIVITY_LO" format_string="%s filter state. %s">
  + <event id="0x0" name="SEVERITY_FILTER_STATE" severity="ACTIVITY_LO" format_string="%s filter state. %d">
  <comment>
  Dump severity filter state
  </comment>
  