MicroPython对蓝牙又做出多个改进

[shaoziyang]

最近Micropython一直对蓝牙进行持续改进。

• docs/library/bluetooth.rst: Fix typo in HR/UART services example.
• extmod/modbluetooth: Make gap_disconnect not raise when disconnected.
• docs/library/bluetooth.rst: Explain how to increase char buffer size.
• esp32: Run NimBLE on the app core.
• extmod/modbluetooth: Improve ringbuf handling.
• extmod/modbluetooth: Fix order of params to IRQ_GATTS_WRITE event.
• docs/library/bluetooth.rst: Clarify gap_advertise adv_data behavior.
• extmod/modbluetooth: Clear gap_advertise payload when data is empty.
• extmod/modbluetooth: Increase maximum connections from 1 to 4.