Remove on hover highlight for annotations

[jorg-vr]

This pull request removes the the highlighting of the code marking when the related annotation is hovered.

This rather minor feature is the cause of browser hanging on pages with a lot of annotations. Improving the speed is not trivial, so I sugget removing the feature until we have a better fix of the speed.

In the most ideal case this feature would be redone using css :has selector, but because this would involve dynamic class names this is non-trivial.

I have identified the following key issues to speed up the javascript case:

• limit the number of marking elements in the html. (This example has more then 900) This could be achieved by wrapping higher ancestors instead of each separate text-node. Which would also fix the non continuous wavy underline in a lot of cases.
• speed up the re render of a single marking element. This can be done by not recreating the tooltip every time. I tried this first, but this was rather finicky because updating instead of destroying the old tooltip led to some inconsistency in the triggering of mouse related events. I can probably fix this by spending some more time on it.

Closes #4749.