Directly mention ChangesListBooleanFilterGroup and
ChangesListStringOptionsFilterGroup so people know what to construct.
Change-Id: I3c105d072889c1da26f94402326ba48635081833
new ChangesListBooleanFilter or ChangesListStringOptionsFilter objects.
When constructing them, you specify which group they belong to. You can reuse
-existing groups (accessed through $special->getFilterGroup), or create your own.
+existing groups (accessed through $special->getFilterGroup), or create your own
+(ChangesListBooleanFilterGroup or ChangesListStringOptionsFilterGroup).
If you create new groups, you must register them with $special->registerFilterGroup.
$special: ChangesListSpecialPage instance