Remove unused markedAsZombie signal

src/abstract_client.cpp

@@ -235,7 +235,6 @@ void AbstractClient::markAsZombie()
     Q_ASSERT(!m_zombie);
     m_zombie = true;
     addWorkspaceRepaint(visibleGeometry());
-    Q_EMIT markedAsZombie();
 }
 
 Layer AbstractClient::layer() const

src/toplevel.h

@@ -568,7 +568,6 @@ public:
 
 Q_SIGNALS:
     void shadeChanged();
-    void markedAsZombie();
     void opacityChanged(KWin::Toplevel* toplevel, qreal oldOpacity);
     void damaged(KWin::Toplevel* toplevel, const QRegion& damage);
     void inputTransformationChanged();

src/unmanaged.cpp

@@ -132,7 +132,6 @@ bool Unmanaged::track(xcb_window_t w)
 void Unmanaged::release(ReleaseReason releaseReason)
 {
     addWorkspaceRepaint(visibleGeometry());
-    Q_EMIT markedAsZombie();
     Deleted* del = nullptr;
     if (releaseReason != ReleaseReason::KWinShutsDown) {
         del = Deleted::create(this);