change size type from int to {int} for video.add_text

[kessenza]

video.add_text requires that font size must be int but it would be great to have it {int} to be able to change size of the font dinamically.
In this way it woud be possible to reduce or increase the size of the font depending on text length to fit it inside a box on screen.
This is possibile with x and y position (to center text inside the box) but not for size