GTK theme treeview style typo/bug fix
Summary:
Fixes a typo in the CSS files which resulted in GTK treeviews being unusable. See picture.
Reviewers: Breeze, VDG, broulik, ngraham
Reviewed By: Breeze, VDG, broulik, ngraham
Subscribers: ngraham, jackg, plasma-devel, Breeze
Differential Revision: https://phabricator.kde.org/D16331