examples: add screenshots to more modules

Adding screenshots and small documentation file to the modules
- corelib
- datavisualization
- external
- opengl
- quick
- sql
- uitools
- webchannel
- webenginewidgets
- some widgets
- xml

Renaming the widgets gallery due to name conflict
with the quick controls gallery, and fixing two
typos from contextinfo.py and hellogl2.py.

Task-number: PYSIDE-841
Pick-to: 6.1
Change-Id: I2705e5d605fa738da0dca906cf6acb4b9d5d3dcd
Reviewed-by: Friedemann Kleint <[email protected]>

3 files changed, 10 insertions, 1 deletions

diff --git a/examples/opengl/hellogl2/doc/hellogl2.png b/examples/opengl/hellogl2/doc/hellogl2.png
new file mode 100644
index 000000000..674ea9fbe
--- /dev/null
+++ b/examples/opengl/hellogl2/doc/hellogl2.png
diff --git a/examples/opengl/hellogl2/doc/hellogl2.rst b/examples/opengl/hellogl2/doc/hellogl2.rst
new file mode 100644
index 000000000..1223e138c
--- /dev/null
+++ b/examples/opengl/hellogl2/doc/hellogl2.rst
@@ -0,0 +1,9 @@
+Hello GL2 Example
+=================
+
+The Hello GL2 example demonstrates the basic use of the OpenGL-related classes
+provided with Qt.
+
+.. image:: hellogl2.png
+   :width: 400
+   :alt: Hello GL2 Screenshot
diff --git a/examples/opengl/hellogl2/hellogl2.py b/examples/opengl/hellogl2/hellogl2.py
index 6dfc032ad..2f170dc90 100644
--- a/examples/opengl/hellogl2/hellogl2.py
+++ b/examples/opengl/hellogl2/hellogl2.py
@@ -232,7 +232,7 @@ class GLWidget(QOpenGLWidget, QOpenGLFunctions):
 
     def __init__(self, transparent, parent=None):
         QOpenGLWidget.__init__(self, parent)
-        super().__init__()
+        QOpenGLFunctions.__init__(self)
 
         self._transparent = transparent
         self._core = QSurfaceFormat.defaultFormat().profile() == QSurfaceFormat.CoreProfile