Update Bluetooth docs to mention Win32 backend

This change updates the Bluetooth documentation to reflect the addition
of the native Win32 backend.

Task-number: QTBUG-40698
Change-Id: I8d2bc2146527a17f1f47fff541730b94f58286fb
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

src/bluetooth/doc/src/bluetooth-index.qdoc

@@ -51,7 +51,7 @@ Currently, the API is supported on the following platforms:
     \li x
     \li x
     \li x
-    \li
+    \li x
 \row
     \li Bluetooth LE Central
     \li x
@@ -59,7 +59,7 @@ Currently, the API is supported on the following platforms:
     \li x
     \li x
     \li x
-    \li
+    \li x
 \row
     \li Bluetooth LE Peripheral
     \li x
@@ -78,10 +78,12 @@ Currently, the API is supported on the following platforms:
     \li
 \endtable
 
-Despite there not being a Win32 port yet, the WinRT backend is automatically used
-if the win32 target platform supports the required WinRT APIs. Minimal requirement is Windows 10 version 1507
-with slightly improved service discovery since Windows 10 version 1607. Therefore Windows 7 and 8.x
-targets are excluded.
+Qt 5.14 adds a native Win32 port supporting Classic Bluetooth on Windows 7 or newer,
+and Bluetooth LE on Windows 8 or newer. It must be enabled at build time by configuration
+option -native-win32-bluetooth. The WinRT backend is used by default if this option is not
+set and the Win32 target platform supports the required WinRT APIs (minimal requirement is
+Windows 10 version 1507, with slightly improved service discovery since Windows 10 version
+1607).
 
 \section1 Overview
 
@@ -115,7 +117,7 @@ import statement in your \c .qml file:
 \section2 Building Qt Bluetooth
 
 Despite the fact that the module can be built for all Qt platforms,
-the module is not ported to all of them. Not supported platforms such as Windows desktop
+the module is not ported to all of them. Not supported platforms
 employ a fake or dummy backend which is automatically selected when the
 platform is not supported. The dummy backend reports appropriate error messages
 and values which allow the Qt Bluetooth developer to detect at runtime that the
@@ -167,6 +169,9 @@ The \l QtBluetooth module exports the following
 \row
     \li qt.bluetooth.winrt
     \li Enables logging of the \l {Qt for WinRT} {WinRT} implementation
+\row
+    \li qt.bluetooth.windows
+    \li Enables logging of the \l {Qt for Windows} {Win32} implementation
 \endtable
 
 Logging categories can be used to enable additional warning and debug output

src/bluetooth/doc/src/bluetooth-overview.qdoc

@@ -49,6 +49,11 @@
 
     Note that the Object Push Profile is not supported on Android.
 
+    Note that the Received Signal Strength Indicator (RSSI), as well as
+    the Manufacturer Specific Data advertised by Bluetooth LE devices are
+    not supported by the Win32 backend. Also, it is only possible to find
+    devices that have been previously paired through Windows Settings.
+
     The following sections describe how to use the Qt Bluetooth C++ API classes
     for the above use cases.
 

src/bluetooth/qbluetoothdevicediscoveryagent.cpp

@@ -78,6 +78,10 @@ Q_DECLARE_LOGGING_CATEGORY(QT_BT)
 
     \note Due to API limitations it is only possible to find devices that have been paired using
     Windows' settings on Windows.
+
+    \note The Win32 backend currently does not support the Received Signal Strength
+    Indicator (RSSI), as well as the Manufacturer Specific Data, or other data
+    updates advertised by Bluetooth LE devices after discovery.
 */
 
 /*!