Add option to force sending text or binary frames to asyncio broadcast() #1694

A text argument to broadcast() similar to how send() handles it would allow me to change a line like

websockets.broadcast(connections, data.decode("utf-8")) (only to immediately encode it again) to
websockets.broadcast(connections, data, text=True)

which would also relieve the code at that point from knowing whether data is bytes or str, only that it needs to go into a "Text" frame.

I've been testing this change to asyncio-broadcast so far with no ill effects.

src/websockets/asyncio/connection.py:

def broadcast(
    connections: Iterable[Connection],
    message: DataLike,
    raise_exceptions: bool = False,
    *,
    text: bool | None = None,
) -> None:
"""
...

"""
    if isinstance(message, str):
        if text is None:
            send_method = "send_text"
        message = message.encode()
    elif isinstance(message, BytesLike):
        if text is None:
            send_method = "send_binary"
    else:
        raise TypeError("data must be str or bytes")

    if text is not None:
        send_method = "send_text" if text else "send_binary"

( in a branch here )

What would be the chances of getting type-overrides backported to 13.x? (Mostly j/k, but I have one test environment with Python 3.8/websockets 13 left and the patch applies the same to the 13.x branch but lacks the change to send())

broadcast-text.patch