title: Language not switching to french on Leaflet Routing Machine
body: <p>I'm using this  <a href="https://github.com/perliedman/leaflet-routing-machine" rel="nofollow noreferrer">plugin</a> , I want to set language as French <strong>fr</strong>, for that I use <code>formatter: new L.Routing.Formatter(language: 'fr')</code> like you can see the code bellow :</p>
  
  <pre><code>L.Routing.control({
    waypoints: [L.latLng(48.8534, 2.3488), L.latLng(44.837789, -0.57918)],
    routeWhileDragging: true,
    show: true,
    formatter: new L.Routing.Formatter({ units: 'metric', language: 'fr' }),
    autoRoute: true
  }).addTo(this.mapInstance);
  </code></pre>
  
  <p>But, the <a href="https://i.stack.imgur.com/tVhJ6.png" rel="nofollow noreferrer">result</a> is always in English 'en'.</p>