fix selection on duplicate line up/down
fix selection on duplicate line up/down

If a line is empty, it's still considered.
BUG: 300649

sandsmark/kate,hlamer/kate,sandsmark/kate,sandsmark/kate,cmacq2/kate,cmacq2/kate,hlamer/kate,hlamer/kate,hlamer/kate,hlamer/kate,jfmcarreira/kate,jfmcarreira/kate,DickJ/kate,cmacq2/kate,hlamer/kate,hlamer/kate,DickJ/kate,jfmcarreira/kate,sandsmark/kate,hlamer/kate,hlamer/kate,DickJ/kate,hlamer/kate,DickJ/kate