Support for <sub> and <sup> tags or custom Markdown syntax for subscripts/superscripts

[manastelavane]

Currently, react-native-markdown-display does not support rendering <sub> and <sup> HTML tags or any markdown-equivalent syntax for subscripts and superscripts.

This is a limitation when trying to display scientific formulas like H₂O, math expressions like x², or even general footnote/superscript content.

Example Use Case:

Markdown input:

H<sub>2</sub>O or H~2~  
x<sup>2</sup> or x^2^

Expected rendered output:

• "H₂O" with 2 as subscript
• "x²" with 2 as superscript

Suggestions:

• Support <sub> and <sup> HTML tags inside markdown
• OR allow a markdown extension like ~text~ for subscript and ^text^ for superscript

Thanks for the awesome library!