PHRAS-2954 Add translation

templates/web/prod/index.html.twig

@@ -733,7 +733,7 @@
                     </div>
                 </div>
                 <div class="box">
-                    <h1>{{  'Language' | trans }} : {{ app['locale'] }}</h1>
+                    <h1>{{  'Language selection' | trans }}</h1>
                     <label class="inline" for="language">
                         <select onchange="window.location = $(this).val();" id="language">
                             {% for code, language in app.getAvailableLanguages() %}