href field of the user mention <a> tag is encoded

[North-West-Wind]

Describe the bug

When mentioning a user in Cinny, the produced href in the <a> tag of formatted_body is encoded. It's not the case of other clients, such as SchildiChat and FluffyChat.

Cinny message source

{ "type": "m.room.message", "sender": "@northwestwind:matrix.northwestw.in", "content": { "msgtype": "m.text", "body": "@discord_895321877109690419:matrix.northwestw.in", "format": "org.matrix.custom.html", "formatted_body": "<a href=\"https%3A%2F%2Fmatrix.to%2F%23%2F%40discord_895321877109690419%3Amatrix.northwestw.in\">@TradeW1nd (bot)</a>" }, "origin_server_ts": 1725023942435, "unsigned": { "membership": "join", "age": 62, "transaction_id": "m1725023942287.7" }, "event_id": "hidden", "room_id": "!hidden:matrix.northwestw.in" }

FluffyChat message source

{ "type": "m.room.message", "sender": "@northwestwind:matrix.northwestw.in", "content": { "msgtype": "m.text", "body": "@[TradeW1nd (bot)] ", "format": "org.matrix.custom.html", "formatted_body": "<a href=\"https://matrix.to/#/@discord_895321877109690419:matrix.northwestw.in\">@[TradeW1nd (bot)]</a>" }, "origin_server_ts": 1725024749022, "unsigned": { "membership": "join", "age": 128 }, "event_id": "hidden", "room_id": "!hiddenmatrix.northwestw.in" }

This causes issues with bridges, Mautrix bridges in particular. They get confused and just show the encoded URI.

Reproduction

1. Set up a Mautrix bridge
2. Send a message mentioning a user
3. The encoded URI gets shown on the non-matrix platform

Expected behavior

The <a> tag in formatted_body should not be URI encoded.

Platform and versions

1. OS: Endeavour OS
2. Browser: Firefox 129.0.2
3. Cinny: v4.1.0
4. Homeserver: matrix.northwestw.in

Additional context

Not sure if this is an intentional design or not. If so, I shall report this to the bridges.