Highlight sentences when mouse hovering logs.

Tell me what you think about that.

> On a sentence page, highlight linked sentences when mouse hovering a related
logs entry. This should help a bit to understand the logs, e.g. what sentence
got created when. It’s probably not very usable for very long logs because the
displayed sentences easily get out of screen, but it’s better than mouse
hovering links back and forth while remembering sentence ids.