Document that `WebSocketResponse.receive()` raises `asyncio.TimeoutError`

[antonagestam]

To be able to do anything useful with the timeout feature of WebSocketResponse.receive() you will probably want to catch the exceptions that occur. It's currently quite hard to find what exceptions will be raised on timeouts without digging through source code. I suggest documenting the fact.

Related issue: #2906
receive() in the documentation/reference: https://aiohttp.readthedocs.io/en/stable/web_reference.html#aiohttp.web.WebSocketResponse.receive

[asvetlov]

.receive() can raise many exception types.
If you want to make a PR for docs fix -- you are welcome.

[mhaoda]

Can I give a try on this document enhancement?

[Dreamsorcerer]

Of course. Seems like it should be a fairly simple change.

[mhaoda]

Thanks, I'll work on it then.