Problem

Currently there is only a circle annotation among the "round" annotations, which can be quite big for long texts.

Proposed solution

Add an ellipse annotation. Equations can be found here (second answer): https://stackoverflow.com/questions/433371/ellipse-bounding-a-rectangle

The code will be very similar to the circle annotation:

but with an ellipse rather than a circle.

There is also a bit of documentation to update, e.g., https://matplotlib.org/stable/tutorials/text/annotations.html