Overview
Include a post's audio files as attachments in the ActivityStreams data used in the fediverse.
Use Case
Originally requested on the forum, specifically:
[...] But assuming I set that up, is there some way to then associate an external non-image URL with a post and have that file included as an attachment in the feed/activitypub?
Implementation
Similar to T709, parse out embedded audio files (base goal: any that were added to a post via an <audio> element), and include them in the attachment array.