Remove references to twitter

Author: wooorm

readme.md

@@ -23,7 +23,6 @@ You can use the many existing plugins or you can make your own.
 
 * to learn HTML, see [MDN][] and [WHATWG HTML][html]
 * for more about us, see [`unifiedjs.com`][site]
-* for updates, see [Twitter][]
 * for questions, see [support][]
 * to help, see [contribute][] or [sponsor][] below
 
@@ -353,8 +352,6 @@ Support this effort and give back by sponsoring on [OpenCollective][collective]!
 
 [html]: https://html.spec.whatwg.org/multipage/
 
-[twitter]: https://twitter.com/unifiedjs
-
 [site]: https://unifiedjs.com
 
 [topic]: https://github.com/topics/rehype-plugin