Remove some unnecessary forward declarations and headers

src/UserSettingsPage.h

@@ -12,15 +12,6 @@
 
 #include <optional>
 
-class Toggle;
-class QLabel;
-class QFormLayout;
-class QComboBox;
-class QFontComboBox;
-class QSpinBox;
-class QHBoxLayout;
-class QVBoxLayout;
-
 class UserSettings final : public QObject
 {
     Q_OBJECT

src/encryption/VerificationManager.h

@@ -14,7 +14,6 @@
 
 class DeviceVerificationFlow;
 class TimelineModel;
-class TimelineModel;
 class TimelineViewManager;
 class RoomlistModel;
 

src/timeline/TimelineViewManager.h

@@ -7,7 +7,6 @@
 #include <QHash>
 #include <QQuickItem>
 #include <QQuickTextDocument>
-#include <QWidget>
 
 #include <mtx/common.hpp>
 #include <mtx/responses/messages.hpp>