Not currently, no.
However, the underlying library we're using supports them, so I'll keep this open to re-visit for 3.5.
Timing on this ended up being pretty good, as I also encountered https://github.com/logaretm/villus/issues/26 :)
This has been added for Craft 3.5.
Most helpful comment
Not currently, no.
However, the underlying library we're using supports them, so I'll keep this open to re-visit for 3.5.