PdfMultiPageView: following search results scrolls around more than necessary

As explained in a comment on https://codereview.qt-project.org/c/qt/qtdeclarative/+/403932 if I use

TableView.positionViewAtCell(Qt.point(0, pageIndex), TableView.Contain, searchResultRect.topLeft);

it ends up positioning the viewport so that the search result is at the upper-left corner of the viewport, every time (except when the search result is too far to the right, so that doing so would exceed the limits of the horizontal scrollbar; that behavior is correct). The idea of the Contain mode was to do less scrolling, but it doesn't have that effect whenever the user has zoomed in far enough that the page is larger than the viewport.

Also, on the first page it scrolls too often, even when the page is smaller than the viewport.

This is not terrible, it's just a bit more disorienting user experience than it needs to be.