Fix _bleio.start_advertising arg check; add doc to SocketPool.socket()

[dhalbert]

• Fixes additional positional arguments failure in requests #5503.
• Fixes directed_to may not allow None anymore #5460, same as (BLE) TypeError: directed_to must be of type Address #5502.

Changes:

• Improve documentation noting that SocketPool.socket() does not take all the arguments that CPython socket.socket() takes.
• Fix arg checking for Adapter.start_advertising(..., directed_to=...).
• Implement passing directed_to arg via HCI in BLE HCI device support. Not tested.

@Neradoc I tested the start_advertising() fix in the REPL, but if you could try too, that would be great.

[Neradoc]

Works, thanks !
Tested on the Circuitplayground Bluefruit with the code with which I discovered the issue.

[jerryneedell]

I don't feel competent to review this. Given @Neradoc successful test it looks good.

[ThomasAtBBTF]

"Implement passing directed_to arg via HCI in BLE HCI device support. Not tested."

Does this mean, that I can find the address of a host somewhere in BLE HCI?

[dhalbert]

"Implement passing directed_to arg via HCI in BLE HCI device support. Not tested."

Does this mean, that I can find the address of a host somewhere in BLE HCI?

No, sorry, I did not add that, so this support is latent.

[ThomasAtBBTF]

@dhalbert that's ok.
Don't hurry!
You anyway move so much ....

[tannewt]

Looks good! Thank you!