Update class names in DUDhain API dox
Reviewers: KDevelop, kfunk
Reviewed By: KDevelop, kfunk
Subscribers: kfunk, kdevelop-devel
Differential Revision: https://phabricator.kde.org/D6682
(cherry picked from commit ce48742a5815f0f1556083ea84eaf0d03faed0bf)