code: function formatChange() {
    var mask = document.getElementById('blocklyMask');
    var languagePre = document.getElementById('languagePre');
    var languageTA = document.getElementById('languageTA');
    if (document.getElementById('format').value == 'Manual') {
      Blockly.hideChaff();
      mask.style.display = 'block';
      languagePre.style.display = 'none';
      languageTA.style.display = 'block';
      var code = languagePre.textContent.trim();
      languageTA.value = code;
      languageTA.focus();
      updatePreview();
    } else {
      mask.style.display = 'none';
      languageTA.style.display = 'none';
      languagePre.style.display = 'block';
      updateLanguage();
    }
    disableEnableLink();
  }
docs: Change the language code format.