Add type annotation to WebSocketEndpoint.encoding (#1003)
Add type annotation to WebSocketEndpoint.encoding (#1003)

* Add type annotation to WebSocketEndpoint.encoding

* Update endpoints.py

Co-authored-by: Florimond Manca <c491f569130f6f25f76edbdf24dcdb8e627dfb7b@gmail.com>
encode/starlette,encode/starlette