Changes

'''BluetoothAdapterEvent''' is carried as the parameter of [[B2G/Bluetooth/WebBluetooth-v2/BluetoothManager#onadapteradded|manager.onadapteradded]] and [[B2G/Bluetooth/WebBluetooth-v2/BluetoothManager#onadapterremoved|manager.onadapterremoved]] event handlers. Applications can know whether the added/removed adapter is default adapter, and get the added [[B2G/Bluetooth/WebBluetooth-v2/BluetoothAdapter|BluetoothAdapter]] object or the address of removed adapter.