Improve Accessibility documentation.

Change-Id: Ifb70d9c6d7b3096e0188e8454191786375296647
Reviewed-by: Geir Vattekar <geir.vattekar@nokia.com>

src/gui/accessible/qaccessible.cpp

@@ -59,11 +59,13 @@ QT_BEGIN_NAMESPACE
 /*!
     \class QAccessible
     \brief The QAccessible class provides enums and static functions
-    relating to accessibility.
+    related to accessibility.
 
     \ingroup accessibility
     \inmodule QtWidgets
 
+    This class is part of \l {Accessibility for QWidget Applications}.
+
     Accessible applications can be used by people who are not able to
     use applications by conventional means.
 
@@ -687,6 +689,8 @@ void QAccessible::updateAccessibility(QObject *o, int who, Event reason)
     \ingroup accessibility
     \inmodule QtGui
 
+    This class is part of \l {Accessibility for QWidget Applications}.
+
     Accessibility tools (also called AT Clients), such as screen readers
     or braille displays, require high-level information about
     accessible objects in an application. Accessible objects provide
@@ -1080,6 +1084,9 @@ QColor QAccessibleInterface::backgroundColor() const
 
 /*!
     \class QAccessibleEvent
+
+    \internal
+
     \brief The QAccessibleEvent class is used to query addition
     accessibility information about complex widgets.
 

src/gui/accessible/qaccessibleobject.cpp

@@ -96,6 +96,8 @@ QList<QByteArray> QAccessibleObjectPrivate::actionList() const
     \ingroup accessibility
     \inmodule QtWidgets
 
+    This class is part of \l {Accessibility for QWidget Applications}.
+
     This class is mainly provided for convenience. All subclasses of
     the QAccessibleInterface that provide implementations of non-widget objects
     should use this class as their base class.

src/widgets/accessible/qaccessiblewidget.cpp

@@ -159,6 +159,8 @@ public:
     \ingroup accessibility
     \inmodule QtWidgets
 
+    This class is part of \l {Accessibility for QWidget Applications}.
+
     This class is convenient to use as a base class for custom
     implementations of QAccessibleInterfaces that provide information
     about widget objects.