docs/library/bluetooth: Add link to aioble.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

docs/library/bluetooth.rst

@@ -13,6 +13,9 @@ concurrently. Pairing (and bonding) is supported on some ports.
 This API is intended to match the low-level Bluetooth protocol and provide
 building-blocks for higher-level abstractions such as specific device types.
 
+.. note:: For most applications, we recommend using the higher-level
+          `aioble library <https://github.com/micropython/micropython-lib/tree/master/micropython/bluetooth/aioble>`_.
+
 .. note:: This module is still under development and its classes, functions,
           methods and constants are subject to change.