option was renamed to `scale` instead of `size` because `scale`
describes the technical fact better than `size`.
Please also see DEVELOPERS message in `hud_element_scale.lua` file if
you’re interested in contributing to this project.
Addresses https://gitlab.com/4w/mtimer/-/issues/16
Since the custom timer formspec is fairly complex (and will be a bit
more complex in the future) the best thing is splitting it off from the
other formspec definitions.
