KateModeMenuList: don't overlap the scroll bar
Summary:
According to T9126, the scroll bar will not overlap the list.
Reviewers: cullmann, KTextEditor
Reviewed By: cullmann, KTextEditor
Subscribers: ngraham, anthonyfieroni, kwrite-devel, kde-frameworks-devel
Tags: Kate, Frameworks
Differential Revision: https://phabricator.kde.org/D26957