test, utils, visualizer: document missing functions and variables in scripts

Silences warnings on Doxygen > 1.9.7.

utils/grid.py

@@ -1388,7 +1388,17 @@ class GtkGraphicRenderer(gtk.DrawingArea):
     ## @var __height
     #  height
     ## @var __buffer_surface
-    #  buffer surface
+    # __buffer_surface
+    ## @var expose
+    #  expose function
+    ## @var size_allocate
+    #  size_allocate function
+    ## @var motion_notify
+    #  motion_notify function
+    ## @var button_press
+    #  button_press function
+    ## @var button_release
+    #  button_release function
     def __init__(self, data):
         """! Initializer
         @param self this object
@@ -1638,6 +1648,14 @@ class MainWindow:
     #  render
     ## @var __dialog
     #  dialog
+    ## @var __set_smaller_cb
+    #  __set_smaller_cb function
+    ## @var __set_bigger_cb
+    #  __set_bigger_cb function
+    ## @var __output_png_cb
+    #  __output_png_cb function
+    ## @var __dialog_response_cb
+    #  __dialog_response_cb function
     def __init__(self):
         """! Initializer
         @param self this object

utils/python-unit-tests.py

@@ -414,6 +414,7 @@ class TestSimulator(unittest.TestCase):
                 return None
                 """
                 super().__init__()
+                ## __python_owns__ flag indicates that Cppyy should not manage the lifetime of this variable
                 self.__python_owns__ = False  # Let C++ destroy this on Simulator::Destroy
                 ## Listen port for the server
                 self.port = port

utils/tests/test-ns3.py

@@ -858,6 +858,7 @@ class NS3ConfigureTestCase(NS3BaseTestCase):
         self.config_ok(return_code, stdout, stderr)
 
         # If nothing went wrong, we should have more executables in the list after enabling the examples.
+        ## ns3_executables
         self.assertGreater(len(get_programs_list()), len(self.ns3_executables))
 
         # Now we disabled them back.
@@ -909,6 +910,7 @@ class NS3ConfigureTestCase(NS3BaseTestCase):
 
         # At this point we should have fewer modules
         enabled_modules = get_enabled_modules()
+        ## ns3_modules
         self.assertLess(len(get_enabled_modules()), len(self.ns3_modules))
         self.assertIn("ns3-network", enabled_modules)
         self.assertIn("ns3-wifi", enabled_modules)
@@ -1032,6 +1034,7 @@ class NS3ConfigureTestCase(NS3BaseTestCase):
             ns3rc_templates = {"python": ns3rc_python_template, "cmake": ns3rc_cmake_template}
 
             def __init__(self, type_ns3rc):
+                ## type contains the ns3rc variant type (deprecated python-based or current cmake-based)
                 self.type = type_ns3rc
 
             def format(self, **args):