Documentation tweaks.

Mostly move widgets classes into the QtMultimediaWidgets module, but
also mark a few mostly internal playlist classes as \internal.  A few other
tweaks.

Change-Id: If0e376410bf2187cafb24f583108c6beb7b910a9
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@nokia.com>

src/multimedia/audio/qsound.cpp

@@ -46,7 +46,7 @@
 
 /*!
     \class QSound
-    \brief The QSound class provides a way to play .wav sound files.
+    \brief The QSound class provides a method to play .wav sound files.
 
     \ingroup multimedia
     \ingroup multimedia_audio
@@ -74,6 +74,10 @@
     static play() function, but it may also play more immediately
     (depending on the underlying platform audio facilities).
 
+    If you require finer control over playing sounds, consider the
+    \l QSoundEffect or \l QAudioOutput classes.
+
+    \sa QSoundEffect
 */
 
 

src/multimedia/playback/qmediaplaylistioplugin.cpp

@@ -45,6 +45,7 @@ QT_BEGIN_NAMESPACE
 
 /*!
     \class QMediaPlaylistReader
+    \internal
 
     \brief The QMediaPlaylistReader class provides an interface for reading a playlist file.
     \inmodule QtMultimedia
@@ -86,6 +87,7 @@ QMediaPlaylistReader::~QMediaPlaylistReader()
 
 /*!
     \class QMediaPlaylistWriter
+    \internal
 
     \brief The QMediaPlaylistWriter class provides an interface for writing a playlist file.
 

src/multimedia/playback/qmediaplaylistnavigator.cpp

@@ -192,6 +192,7 @@ int QMediaPlaylistNavigatorPrivate::previousItemPos(int steps) const
 
 /*!
     \class QMediaPlaylistNavigator
+    \internal
 
     \brief The QMediaPlaylistNavigator class provides navigation for a media playlist.
     \inmodule QtMultimedia

src/multimedia/playback/qmediaplaylistprovider.cpp

@@ -48,6 +48,7 @@ QT_BEGIN_NAMESPACE
 
 /*!
     \class QMediaPlaylistProvider
+    \internal
 
     \brief The QMediaPlaylistProvider class provides an abstract list of media.
     \inmodule QtMultimedia

src/multimedia/radio/qradiotuner.cpp

@@ -87,7 +87,7 @@ namespace
     You can change between the frequency bands using setBand() however it is recommended
     that you check to make sure the band is available first using isBandSupported().
 
-    \sa {Radio Overview}
+    \sa QRadioData, {Radio Overview}
 */