The form at the top of Special:CheckUserLog should be updated to use OOUI.
What needs doing
The following changes should be made in SpecialCheckUserLog::displaySearchForm:
- The call to HTMLForm::factory should be updated to pass in 'ooui' as the type, instead of 'table'
- The monthyear form field should be updated to be type 'date' instead of 'info'
- The new date field should have the label "From date (and earlier):"
The new date field will also need to submit data that is compatible with what the CheckUserLogPager expects. Either the field or the CheckUserLogPager will need to be adapted.