Use real Attchment types instead of Document

[pfefferle]

Use Audio and Video instead of Document.

Proposed changes:

Other information:

• Have you written new tests for your changes, if applicable?

Testing instructions:

• Go to '..'

Changelog entry

• Automatically create a changelog entry from the details below.

Changelog Entry Details

Significance

• Patch
• Minor
• Major

Type

• Added - for new features
• Changed - for changes in existing functionality
• Deprecated - for soon-to-be removed features
• Removed - for now removed features
• Fixed - for any bug fixes
• Security - in case of vulnerabilities

Message

Use Audio and Video type for Attachments, instead of the very generic Document type.

[obenland]

Would a unit test help to make sure we get the expected output? Probably more cosmetics, as it's really more about third-party consumers understanding it correctly?

[pfefferle]

We had some isses with attachments not showing up properly on Mastodon and I thought it might be because of them changing the requirments... but it seems to be not the solution to that because Mastodon is still using Document 🤔

[mattwiebe]

I like the idea of sending proper Attachment types. But maybe not if it doesn't fix anything heh