message: qt: Drop BitcoinGUI::toggleHideAction member
  Also dropped useless tooltip.
diff: @@ -155,7 +155,6 @@ private:
  QAction* receiveCoinsAction = nullptr;
  QAction* receiveCoinsMenuAction = nullptr;
  QAction* optionsAction = nullptr;
  - QAction* toggleHideAction = nullptr;
  QAction* encryptWalletAction = nullptr;
  QAction* backupWalletAction = nullptr;
  QAction* changePassphraseAction = nullptr;
  