Update content/client-server-api/_index.md

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

content/client-server-api/_index.md

@@ -226,8 +226,6 @@ return a standard error response of the form:
 }
 ```
 
-{{% changed-in v="1.10" %}}: `retry_after_ms` property deprecated in favour of `Retry-After` header.
-
 Homeservers SHOULD include a [`Retry-After`](https://www.rfc-editor.org/rfc/rfc9110#field.retry-after)
 for any response with a 429 status code.
 
@@ -235,6 +233,7 @@ The `retry_after_ms` property MAY be included to tell the client how long
 they have to wait in milliseconds before they can try again. This property is
 deprecated, in favour of the `Retry-After` header.
 
+{{< changed-in v="1.10" >}}: `retry_after_ms` property deprecated in favour of `Retry-After` header.
 ### Transaction identifiers
 
 The client-server API typically uses `HTTP PUT` to submit requests with