Fix lang toggle

This is not perfect as the toggle is not set to the right position when
the site is reload but as @Wal_ said he would refactor, I just made a
working sample good enough imo

frontend/src/App.vue

@@ -2,7 +2,7 @@
 	import 'https://kit.fontawesome.com/fb3bbd0a95.js'
 	import { toast } from 'vue3-toastify';
 	import { ref } from 'vue'
-  import i18n from './i18n.js'
+  import i18n, { setLang } from './i18n.js'
   import Inscription from "./Inscription.vue"
 
 
@@ -50,7 +50,7 @@
             </a></li>
 
         <li style="float:right; margin-top:7.5px;" title="Language">
-            <input type="checkbox" v-model="toggle" true-value="FR" false-value="EN" class="theme-checkbox">
+            <input type="checkbox" @:click="setLang( toggle? 'fr' : 'en' )" v-model="toggle" class="theme-checkbox">
         </li>
       </ul>
     </div>