Superscript notation in markdown does not work anymore

Summary

The superscript notation ^ does not work since the transition to CommonMark I believe.

Steps to reproduce

Type 1^st in any markdown input.

Example Project

The comment of this issue reproduces this issue: 1^st

What is the current bug behavior?

It displays the superscript character ^.

What is the expected correct behavior?

1^st should render with a superscript st.

Output of checks

This bug happens on GitLab.com.