Attach progress details to the toggle progress details button

The popup is corresponding to the button (and the summary progress bar),
and that automatically also moves it away from the right border a bit.

Task-number: QTCREATORBUG-19308
Change-Id: Ie6f72f19552285586395776b175ca142f56c7d6e
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/coreplugin/progressmanager/progressmanager.cpp

@@ -344,6 +344,7 @@ void ProgressManagerPrivate::init()
     connect(toggleProgressView, &QAction::toggled,
             this, &ProgressManagerPrivate::progressDetailsToggled);
     toggleButton->setDefaultAction(cmd->action());
+    m_progressView->setReferenceWidget(toggleButton);
 
     updateVisibility();