oEmbed spec implementation

[JulianusIV]

Description

Discord does not seem to fully implement the oEmbed spec, specifically section 4 specifies that providers may implement discovery via elements in the served html OR Link headers.
From what I can tell/what i tested Discord only accepts the former

Steps to Reproduce

1. Implement some valid oEmbed setup on a public website using the header discovery method
2. check the embed using the embed debugger - just to be sure its valid also use something like iframely's embed debugger
3. change over to using link element discovery
   you should see that the first method will not work, while the second does

Expected Behavior

Discord should detect and accept both discovery methods, and generate the same embed when served with same data with either method

Current Behavior

Currently Discord does not display an embed when being served a link header instead of a link element

Screenshots/Videos

No response

Client and System Information

I implemented the server serving the website using Actix web