title: Detect click and get text of QTableWidget header, how?
body: <p>I see how to detect click in a <code>QTableWidget</code> cell by watching the <code>cellClicked(int row, int column)</code> signal (code below).</p>
  
  <p>I would like to do the same for the cells of the horizontal header and get the text of the clicked header cell. How do I do that?</p>
  
  <pre><code>// mainwindow.h
  class MainWindow : public QMainWindow {
      Q_OBJECT
      QWidget widget;
      QVBoxLayout vLayout {&amp;widget};
      QStringList headers {"asdca", "asdcad", "asdcadca"};
      QTableWidget table {5, headers.size()};
  public:
      MainWindow(QWidget *parent = 0);
      ~MainWindow() {}
  };
  
  // mainwindow.cpp
  MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) {
      setCentralWidget(&amp;widget);
      vLayout.addWidget(&amp;table);
      table.setHorizontalHeaderLabels(headers);
      connect(&amp;table, &amp;QTableWidget::clicked, []{
         qDebug() &lt;&lt; "click!!" ;
      });
  }
  </code></pre>