WordPress automatically replaces “raw” emoji data in post content with images from the Twemoji library as content is rendered. I enter emojis manually via MacOS’s default interface (CTRL + CMD + Spacebar). I have not (yet) seen anything for using the :shortcode: syntax similar to Slack and others, though that would be really interesting in some contexts.

Hope that helps! Happy to expand if not. 🤓

I’m still new at Webmentions, but I’m taking a stab at replying by linking to your reply. Fingers crossed!