Update changelog

Author: devonh

CHANGES.md

@@ -21,7 +21,7 @@
 
 ### Internal Changes
 
-- MSC3861: load the issuer and account management URLs from OIDC discovery. ([\#17407](https://github.com/element-hq/synapse/issues/17407))
+- Update [MSC3861](https://github.com/matrix-org/matrix-spec-proposals/pull/3861) implementation: load the issuer and account management URLs from OIDC discovery. ([\#17407](https://github.com/element-hq/synapse/issues/17407))
 - Pre-populate room data used in experimental [MSC3575](https://github.com/matrix-org/matrix-spec-proposals/pull/3575) Sliding Sync `/sync` endpoint for quick filtering/sorting. ([\#17512](https://github.com/element-hq/synapse/issues/17512), [\#17632](https://github.com/element-hq/synapse/issues/17632), [\#17633](https://github.com/element-hq/synapse/issues/17633), [\#17634](https://github.com/element-hq/synapse/issues/17634), [\#17635](https://github.com/element-hq/synapse/issues/17635), [\#17636](https://github.com/element-hq/synapse/issues/17636), [\#17641](https://github.com/element-hq/synapse/issues/17641), [\#17654](https://github.com/element-hq/synapse/issues/17654), [\#17673](https://github.com/element-hq/synapse/issues/17673))
 - Store sliding sync per-connection state in the database. ([\#17599](https://github.com/element-hq/synapse/issues/17599), [\#17631](https://github.com/element-hq/synapse/issues/17631))
 - Make the sliding sync `PerConnectionState` class immutable. ([\#17600](https://github.com/element-hq/synapse/issues/17600))