add isFixedSize implementation

Yuhang Zhao

2023-12-05 d02f3b0bc32f711bf33a7fd288185963e9e96189

 src/core/corewindowagent.h

@@ -11,9 +11,7 @@

    class QWK_CORE_EXPORT CoreWindowAgent : public QObject {
        Q_OBJECT
        Q_DISABLE_COPY(CoreWindowAgent)
        Q_DECLARE_PRIVATE(CoreWindowAgent)

    public:
        ~CoreWindowAgent() override;