qtui: Always accept closeEvent() on dock windows

Qt 6 appears to send close events to all windows at QApplication
termination. Ignoring the event at this point can cause a hang or
a crash (due to DockWidget::closeEvent being called twice).

Author: jlindgren90

src/qtui/main_window.cc

@@ -67,31 +67,30 @@ class DockWidget : public QDockWidget
     }
 
 protected:
-    void closeEvent(QCloseEvent * event) override
-    {
-        in_event = true;
-        m_item->user_close();
-        event->ignore();
-        in_event = false;
-    }
+    void closeEvent(QCloseEvent * event) override { close_for_event(event); }
 
     void keyPressEvent(QKeyEvent * event) override
     {
         auto mods = Qt::ShiftModifier | Qt::ControlModifier | Qt::AltModifier;
         if (!(event->modifiers() & mods) && event->key() == Qt::Key_Escape &&
             isFloating())
         {
-            in_event = true;
-            m_item->user_close();
-            event->accept();
-            in_event = false;
+            close_for_event(event);
             return;
         }
 
         QDockWidget::keyPressEvent(event);
     }
 
 private:
+    void close_for_event(QEvent * event)
+    {
+        in_event = true;
+        m_item->user_close();
+        in_event = false;
+        event->accept();
+    }
+
     audqt::DockItem * m_item;
     bool in_event = false;
 };