Previously, we always assumed that elements would be scrolled to the top of the
page, when calling `element.scrollIntoView()`. This is not true for elements
that cannot be scrolled to the top, e.g. when the viewport height is larger than
the height of the content after the element (common for small sections near the
end of the page).
In such cases, we would unnecessarily scroll up to account for the static
toolbar, which was unnecessary (since the element was not behind the toolbar
anyway) and caused ScrollSpy to fail to identify the scrolled-to section as
active.
This commit fixes it by ensuring that we do not scroll more than necessary in
order to align the top of the element with the bottom of the toolbar.
Fixes#17452
709a3f6de7