Superscript for 1st, 2nd, 3rd, 4th, etc.

I don't know what they're called exactly, but these cases need to be properly formatted in the manuscript.

- 1st
- 2nd
- 3rd
- 4th
- etc

<img width="344" height="37" alt="Image" src="https://github.com/user-attachments/assets/6adf2ffb-eee1-4d22-b353-f88304e3f6f6" />

This'll probably be some simple regex, handle 1-3 uniquely, and everything beyond that with `th`.