[WebDriver BiDi] Add CDDL for Events (#653)

Author: Lightning00Blade

index.bs

@@ -5931,6 +5931,13 @@ with data for a descriptor read operation by sending the following message:
 
 ### Events ### {#bidi-events}
 
+<pre highlight="cddl" class="cddl remote-cddl local-cddl">
+BluetoothEvent = (
+  bluetooth.RequestDevicePromptUpdated //
+  bluetooth.GattConnectionAttempted //
+)
+</pre>
+
 #### The bluetooth.requestDevicePromptUpdated Event #### {#bluetooth-requestdevicepromptupdated-event}
 
 <pre highlight="cddl" class="cddl local-cddl">