[Site Feature] Link Previews

Links in posts and comments now display a hover-preview when linking to LessWrong content.

For instance, this link to an old post by Scott Alexander will display the title, first couple paragraphs, and other meta-data.

For comments, it will display the post-name and the comment-in-question, such as on this shortform comment by Buck about effective tutoring.

We’re considering ways to effectively do hover previews for particular common external links (such as wikipedia and arxiv), but for the immediate future, all external links just provide a simple “url” hoveover.