Group header include

Header parts:

PVR_ERROR DeleteChannel(const kodi::addon::PVRChannel& channel) override;
PVR_ERROR RenameChannel(const kodi::addon::PVRChannel& channel) override;
PVR_ERROR OpenDialogChannelSettings(const kodi::addon::PVRChannel& channel) override;
PVR_ERROR OpenDialogChannelAdd(const kodi::addon::PVRChannel& channel) override;
PVR_ERROR OpenDialogChannelScan() override;
PVR_ERROR CallChannelMenuHook(const kodi::addon::PVRMenuhook& menuhook, const kodi::addon::PVRChannel& item) override;