Doc: Update info on Qt for Python app wizards

Move the section higher up in "Creating projects" and add a
screenshot of the wizard.

Change-Id: Ifc48026162ff58d58ef22673d3113cb185d1c887
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

doc/src/projects/creator-only/creator-projects-creating.qdoc

@@ -256,6 +256,8 @@
     For more information about creating Qt Quick projects, see
     \l {Creating Qt Quick Projects}.
 
+    \include creator-python-project.qdocinc python project wizards
+
     \section1 Adding Files to Projects
 
     You can use wizards also to add individual files to your projects.
@@ -408,8 +410,6 @@
     The above functions are also available in the context menu in the
     \uicontrol Projects view.
 
-    \include creator-python-project.qdocinc python project wizards
-
     \section2 Creating OpenGL Fragment and Vertex Shaders
 
     Qt provides support for integration with OpenGL implementations on all

doc/src/python/creator-python-project.qdocinc

@@ -42,22 +42,28 @@
     use \c {.pyqtc} files, but we recommend that you choose \c{.pyproject} files
     for new projects.
 
-    The Window wizard adds the following imports to the \c {main.py}
+    The \uicontrol {Qt for Python - Window} wizard enables you to create a
-    file to provide access to the QApplication and QMainWindow classes
+    Python source file for a new class that you can add to a Python project.
-    in the Qt Widgets module:
+    Specify the class name, base class, and and source file for the class.
+
+    \image qtcreator-python-wizard-app-window.png
+
+    The Window wizard adds the imports to the source file to provide
+    access to the QApplication and the base class you selected in the Qt
+    Widgets module:
 
     \badcode
     import sys
-    from PySide2.QtWidgets import QApplication, QMainWindow
+    from PySide2.QtWidgets import QApplication, QWidget
     \endcode
 
-    The Window wizard also adds a \c MainWindow class that inherits from
+    The Window wizard also adds a main class with the specified name that
-    QMainWindow:
+    inherits from the specified base class:
 
     \badcode
-    class MainWindow(QMainWindow):
+    class MyWidget(QWidget):
         def __init__(self):
-        QMainWindow.__init__(self)
+            QWidget.__init__(self)
     \endcode
 
     Next, the Window wizard adds a main function, where it creates a
@@ -68,13 +74,12 @@
     \badcode
     if __name__ == "__main__":
         app = QApplication([])
-        ...
     \endcode
 
     Next, the Window wizard instantiates the \c MainWindow class and shows it:
 
     \badcode
-        window = MainWindow()
+        window = MyWidget()
         window.show()
         ...
     \endcode
@@ -86,7 +91,7 @@
         sys.exit(app.exec_())
     \endcode
 
-    The Empty wizard adds similar code to the \c {main.py} file, but it does
+    The Empty wizard adds similar code to the source file, but it does
     not add any classes, so you need to add and instantiate them yourself.
 
     For examples of creating Qt for Python applications, see