When "Hide whitespace changes" is selected, changes to trailing whitespace are

shown as equal instead of a replace. Unfortunately, the next/previous keyboard

shortcuts were still stopping to highlight these chunks.
This change fixes up _getNextAnchor to take into account whether or not the

parent chunk of the anchor is dimmed or not.

Created a diff with some whitespace changes, hid those changes, and then

browsed around with the keyboard. Made sure that it worked as expected when the

changes were shown.