Add Superscript Support

[SeloSlav]

Issue Description: The library lacks support for superscript formatting, limiting users from including superscript annotations within the front matter metadata.

Proposed Solution: Extend the library to incorporate superscript support, enabling users to utilize superscripts in front matter metadata for references, footnotes, or scientific notations.

Example Text:

Research abounds linking inflammation to mental health disorders. A study by Miller et al. (2016) demonstrated that chronic inflammation can disrupt normal brain function, leading to cognitive decline**^3^**.

**^3^**: [Miller A.H., Maletic V., Raison C.L. (2009). Inflammation and its discontents: the role of cytokines in the pathophysiology of major depression. Biological psychiatry, 65(9), 732–741.](https://doi.org/10.1016/j.biopsych.2008.11.029)