bluetooth: Rename to WebBluetooth in preparation for new WebBluetooth flag.

Source/modules/bluetooth/BluetoothDiscovery.idl

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // https://webbluetoothcg.github.io/web-bluetooth/#idl-def-bluetoothdiscovery
 
 [
     GarbageCollected,
     NoInterfaceObject,
-    RuntimeEnabled=Bluetooth,
+    RuntimeEnabled=WebBluetooth,
 ] interface BluetoothDiscovery {
     [CallWith=ScriptState] Promise<BluetoothDevice> requestDevice (
         // Implement requestDevice: http://crbug.com/420284
         // sequence<BluetoothScanFilter> filters, optional RequestDeviceOptions options
         );
 };