Fix clipping of the sidebar when headers are long and result in multiple lines in the sidebar

[eLtMosen]

          (although this clipping is a bug and should be fixed separately)

Originally posted by @FlorentRevest in #236 (comment)

[eLtMosen]

I can not find where the style="top: is added via/to one of the classes sidebar hidden-print affix-bottom when the bottom of the page is reached.
You can see in this screen recording that manipulating the ´top´ parameter shifts the sidebar up accordingly.
And somehow top only gets added when scrolling to bottom and and removed when scrolling back up.
But the value that gets added is much too low by factor of 10.

sidebar-clipping-2023-04-11_15.26.43.mp4

[eLtMosen]

Keeping this open despite the mitigating merge of #355 (review)
Since the issue is still present in the Documentation -> Building Asteroid pages for instance.
And someone actually fixing the bootstrap sidebar behavior with long lists would be very welcome.