RDoc escapes <sup> tags

[cstyles]

The documenetation for the Regexp class in the standard library uses <sup> which is escaped as you can see here:

https://ruby-doc.org/core-3.0.1/Regexp.html#class-Regexp-label-Capturing

Parentheses can be used for capturing. The text enclosed by the n^th group of parentheses can be subsequently referred to with n. Within a pattern use the backreference \n; outside of the pattern use MatchData[n].

Can we allow <sup> tags? I believe that, in addition to HTML, some Markdown flavors support <sup> and <sub>. For example, GitHub lets me do this: regular ^superscript _subscript