@odoben Not that I know of, unfortunately. There's still no plan on Mastodon's end to add posting rich text, the update is just for receiving it, as you can see on this PR. Links have been one of the only things that Mastodon doesn't sanitize from posts for a long time now, at least as long as I've been using Mastodon.

EDIT: They are apparently working on Markdown as the standard for posted messages, as seen here, but right now it doesn't look like a lot of work has been done since they're still ironing out the details.