Might as well set the proper text in the menu.

It now shows "Show" or "Hide" Status Bar depending on the current state.

src/ui/MainWindow.cc

@@ -642,6 +642,7 @@ void MainWindow::showStatusBarCallback(bool checked)
 {
     _showStatusBar = checked;
     checked ? statusBar()->show() : statusBar()->hide();
+    _ui.actionStatusBar->setText(checked ? "Hide Status Bar" : "Show Status Bar");
 }
 
 void MainWindow::closeEvent(QCloseEvent *event)