QmlDesigner: Use Qt5-style connect

+ De-slot where possible

Change-Id: Ibd2edbef7b7712aba20593bd0417940e828e0c9c
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/components/debugview/debugviewwidget.cpp

@@ -36,7 +36,8 @@ namespace Internal {
 DebugViewWidget::DebugViewWidget(QWidget *parent) : QWidget(parent)
 {
     m_ui.setupUi(this);
-    connect(m_ui.enabledCheckBox, SIGNAL(toggled(bool)), this, SLOT(enabledCheckBoxToggled(bool)));
+    connect(m_ui.enabledCheckBox, &QAbstractButton::toggled,
+            this, &DebugViewWidget::enabledCheckBoxToggled);
 }
 
 void DebugViewWidget::addLogMessage(const QString &topic, const QString &message, bool highlight)