Simplify full line annotation markers

[jorg-vr]

This pull request creates only a single marker for annotations that span a full line.

In a complex example that reduced the number of rendered marker webcomponents from 948 to 433

• Tests were added
• Documentation update can be found at dodona-edu/dodona-edu.github.io#
• We learned with dolos that using ... isn't a good idea with variable length arrays. This had unexpected performance implications.
• Don recreate tooltips every time

Closes # .

[jorg-vr]

There is already a more relevant speedup included in #4643
When reviewing #4643 we also decided that we will do the markings on hidden text, making these changes irrelevant