[feat]: add support for subscript and superscript modifiers

[lucerowb]

A clear and concise description of what the feature is

I had an issue when adding a release notes that contained references (bibliography), I had to mention them in some place, the documentation on google docs had used superscript to reference these , but strapi had no ability to mark it as superscript or subscript.

Why should this feature be included?

add modifiers like subscript and superscript

Please provide an example for how this would work

<BlocksRenderer
              key={key}
              content={content}
              blocks={{
                paragraph: ParagraphNode,
                heading: HeadingNode,
                quote: QuoteNode,
                list: ListNode,
                image: ImageNode,
                "list-item": ListItemNode,
                code: CodeNode,
                link: LinkNode,
              }}
              modifiers={{
                bold: BoldModifier,
                italic: ItalicModifier,
                strikethrough: strikethroughModifier,
                underline: underlineModifier,
                code: CodeModifier,
                superscript: SuperScriptModifier,
                subscript: SubScriptModifier,
              }}
            />