Drop Qt5: Various plugins: Get rid of QOverload

Change-Id: I4913044f8897fd3449dbb537e4af6785eb3ad447
Reviewed-by: hjk <hjk@qt.io>

src/plugins/modeleditor/modeleditor.cpp

@@ -321,7 +321,7 @@ void ModelEditor::init()
     toolbarLayout->addWidget(openParentButton);
 
     d->diagramSelector = new QComboBox(d->toolbar);
-    connect(d->diagramSelector, QOverload<int>::of(&QComboBox::activated),
+    connect(d->diagramSelector, &QComboBox::activated,
             this, &ModelEditor::onDiagramSelectorSelected);
     toolbarLayout->addWidget(d->diagramSelector, 1);
     toolbarLayout->addStretch(1);