Allow subscript and superscript functions

[virgile-dev]

Is your feature request related to a problem? Please describe.
In order to type x₃ x³
I have to copy paste it form another website.

Describe the solution you'd like
I'd like to be able to simply be able to write x^3 and x_3

Describe alternatives you've considered
Have a LaTeX inline block.

Additional context
Add any other context or screenshots about the feature request here.

Bonus
[x] I'm a sponsor and would appreciate if you could look into this sooner than later 💖

[woutervroege]

linking product goal: TypeCellOS/Product#42