Allow sorting on additional name fields.

Participants page Go to [Site administration ► Users ► Permissions ► User policies] and change the full name format (fullnamedisplay) setting to at least include one of the additional name fields (firstnamephonetic, lastnamephonetic, middlename, alternatename). Update some student names to have these additional name fields filled out. Go to the participants page of a course. Check that the table header has the enabled additional name fields present. Make sure that you can sort the names using these additional name fields. Administration user list Go to [Site administration ► Users ► Permissions ► User policies] and change the Alternative full name format (alternativefullnameformat) setting to at least include one of the additional name fields (firstnamephonetic, lastnamephonetic, middlename, alternatename). To to [Site administration ► Users ► Accounts ► Browse list of users] . Check that the enabled alternative name is visible in the header. Also check that you can sort the users using these headings. Enrolment page Go to an enrolment page in a course [Administration ► Course administration ► Users ► Enrolled users] . Check that the enabled alternative name is visible in the header. Also check that you can sort the users using these headings. Unit tests Run the following unit test: phpunit lib/tests/moodlelib_test.php and report back if there are any failures. Behat tests Run the following behat test: lib/tests/behat/table_sorting.feature and report back if there are any failures.