Doc: add use case 'SELECT List in report, SIP encoded'

Documentation/UseCase.rst

@@ -396,6 +396,7 @@ SELECT list in report, SIP encoded
 * In a report create a dropdown list with the last 20 years.
 * By selecting a year, the page will be reloaded with SIP parameter `filterYear=<year>`
 * In table `cnt` are at least 20 records. The table has a column `id`, starting at 1.
+* The parameter `filterYear` can't be manipulated by the user.
 
 Example::