Cleanup: remove multiple language JS

[Wolfr]

Remove this part of the code from prototype-nav.js:

/**
 * Multilanguage logic
 */

 function displayLanguageLabels(lang) {
  // Switch label on this page
  $('[data-lang][data-lang!='+lang+']').css('display', 'none')
  $('[data-lang='+lang+']').css('display', 'inline-block')
 }

 function checkLangSelected(lang) {
  $('#'+lang+'.br-prototype-langselector').prop('checked', true);
 }

$('.br-prototype-langselector').on('change',function() {
  var newLang = this.value;
  // Switch label on this page
  displayLanguageLabels(newLang)
  // Persist language selection
  navState.langSelected = newLang;
  saveNavState();
});

// Execute on each page refresh
checkLangSelected(navState.langSelected);
displayLanguageLabels(navState.langSelected);

We could work on removing any related language code.

[Wolfr]

Fixed in 1.29.1.