hitTestDisplay
Maps a viewport point to the page under it, in the page's display space: points from the top-left corner of the page as it is shown, y down, with its rotation applied, whatever the format. Null when the point lands on background or spacing.
Search hits, highlights and the geometry of io.github.yuroyami.kitepdf.core.KiteStructuredText use this space, so a point from here can mark the page where the reader tapped. hitTest gives the page's own space instead (#432).