Doc: Add Qt Quick Dialogs to Qt Quick submodules list

And add a landing page for Qt Quick Dialogs.

Change-Id: I0c2611bf5cdbf9937b4fd94228915553d8b3bb77
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

src/imports/dialogs/plugin.cpp

@@ -55,9 +55,36 @@
 
 QT_BEGIN_NAMESPACE
 
+
+/*!
+    \group dialogs
+    \title Dialogs
+*/
+
+/*!
+    \page qtquickdialogs-index.html
+    \title Qt Quick Dialogs
+
+    \brief Qt Quick Dialogs submodule
+
+    The submodule is new in Qt 5.1.
+
+    \section1 Dialogs
+
+    \annotatedlist dialogs
+
+    \section1 Related information
+
+    \section2 Reference
+     \list
+      \li \l{Qt Quick Dialogs QML Types}{Qt Quick Dialogs QML Types}
+     \endlist
+
+*/
+
 /*!
     \qmlmodule QtQuick.Dialogs 1
-    \title Qt Quick Dialog QML Types
+    \title Qt Quick Dialogs QML Types
     \ingroup qmlmodules
     \brief Provides QML types for standard file, color picker and message dialogs
 

src/imports/dialogs/qquickplatformcolordialog.cpp

@@ -53,7 +53,7 @@ QT_BEGIN_NAMESPACE
     \qmltype ColorDialog
     \instantiates QQuickPlatformColorDialog
     \inqmlmodule QtQuick.Dialogs 1
-    \ingroup qtquick-visual
+    \ingroup dialogs
     \brief Dialog component for choosing a color.
     \since Qt 5.1
 

src/imports/dialogs/qquickplatformfiledialog.cpp

@@ -53,7 +53,7 @@ QT_BEGIN_NAMESPACE
     \qmltype FileDialog
     \instantiates QQuickPlatformFileDialog
     \inqmlmodule QtQuick.Dialogs 1
-    \ingroup qtquick-visual
+    \ingroup dialogs
     \brief Dialog component for choosing files from a local filesystem.
     \since Qt 5.1
 

src/quick/doc/src/qtquick.qdoc

@@ -125,6 +125,8 @@ Additional Qt Quick information:
     system for Qt Quick
     \li \l{QtQuick.Window 2}{Window} - contains types for creating
     top-level windows and accessing screen information
+    \li \l{QtQuick.Dialogs 1}{Dialogs} - contains types for creating and
+    interacting with system dialogs
     \endlist
 \li \l{Qt Quick Release Notes} - list of changes and additions in the Qt Quick
 \li \l{Qt Quick Code Samples} - list of all Qt Quick examples