fix: include declarations

The QProcess header needs to be included here, for QTimer usage in the header a
forward declaration is enough. These are both regressions due to changes in Qt.

Author: romangg

kcm/kcm.cpp

@@ -32,6 +32,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <KPluginFactory>
 #include <KSharedConfig>
 
+#include <QProcess>
 #include <QTimer>
 
 K_PLUGIN_CLASS_WITH_JSON(KCMKDisplay, "kcm_kdisplay.json")

kcm/kcm.h

@@ -20,6 +20,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <KQuickManagedConfigModule>
 
+class QTimer;
+
 namespace Disman
 {
 class ConfigOperation;