update style guide link to lib

Author: KianNH

src/content/docs/style-guide/components/footnotes.mdx

@@ -7,7 +7,7 @@ To create footnotes, use the following syntax:
 ```mdx live
 You can use GitHub Flavoured Markdown footnotes![^1]
 
-[^1]: Powered by [littlefoot.js](https://littlefoot.js.org)
+[^1]: Powered by [tippy.js](https://atomiks.github.io/tippyjs/)
 ```
 
 Refer to [Footnotes](/style-guide/formatting/footnotes/) to learn when to use them.