Doc: Add doc to Graphics View Flow Layout example

Change-Id: Id3965d099222607cee4252bbb33c6a1e9c17765a
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>

examples/widgets/doc/src/graphicsview-flowlayout.qdoc

@@ -36,5 +36,17 @@
 
     \image graphicsflowlayout-example.png
 
-    See the \l{Flow Layout Example} for a corresponding widget-based example.
+    This example uses a Graphics View to display the widget, which is a more
+    customizable approach than displaying the flow layout in the application
+    window (See \l {Flow Layout Example}).
+
+    Graphics View Flow Layout snippet:
+
+    \snippet graphicsview/flowlayout/main.cpp 1
+
+    Flow Layout Example snippet:
+
+    \snippet layouts/flowlayout/main.cpp 1
+
+
 */

examples/widgets/graphicsview/flowlayout/main.cpp

@@ -47,7 +47,7 @@
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
-
+//! [1]
 #include "window.h"
 
 #include <QApplication>
@@ -68,3 +68,4 @@ int main(int argc, char *argv[])
 
     return app.exec();
 }
+//! [1]

examples/widgets/layouts/flowlayout/main.cpp

@@ -47,7 +47,7 @@
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
-
+//! [1]
 #include <QApplication>
 
 #include "window.h"
@@ -59,3 +59,4 @@ int main(int argc, char *argv[])
     window.show();
     return app.exec();
 }
+//! [1]