doc fixes

docs/reference/devices/on-notified.md

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+# On Signal Strength Changed
+
+Register code to run when the signal strength of the paired device changes.
+
+### ~hint
+
+The functions in the ``devices`` namespace allow the BBC micro:bit to communicate with a separate (remote) device, 
+such as a smartphone, over Bluetooth (Smart).
+The set of supported events will depend on the remote device and the BBC micro:bit apps available for the remote device.
+
+### ~
+
+
+```sig
+devices.onNotified(MesDeviceInfo.IncomingCall, () => {})
+```
+
+### Parameters
+
+* ``body``: code to run when the signal strength changes.
+
+### Examples
+
+Display the signal strength on screen:
+
+```blocks
+devices.onNotified(MesDeviceInfo.IncomingCall, () => {
+    basic.showString("RING RING")
+})
+```
+
+### See Also
+
+[tell remote control to](/reference/devices/tell-remote-control-to), [raise alert to](/reference/devices/raise-alert-to), [signal strength](/reference/devices/signal-strength)
+
+```package
+microbit-devices
+```