Fix typos in the start_advertising() param docs

[andrewguest]

I noticed there are two small typos in the parameters for the _bleio.Adapter.start_advertising() method. In the Parameters list, two lines had the parameter name and data type values switched. The data type should be listed after :param and before the parameter's name.

The two parameters are currently listed as:

• int (tx_power) – transmitter power while advertising in dBm
• Address (directed_to) – peer to advertise directly to

The data type should be in the parentheses, not the parameter's name:

• tx_power (int) – transmitter power while advertising in dBm
• directed_to (Address) – peer to advertise directly to

[tannewt]

Thank you!