lang: translation of 404 window title

frontend/static/js/lang/en.json

@@ -27,5 +27,6 @@
 	"registerFormPassword": "Password",
 	"registerFormButton": "Register",
 	"registerAlreadyAccount": "Already have an account?",
-	"registerLogin": "Login"
+	"registerLogin": "Login",
+	"404WindowTitle": "Not Found"
 }

frontend/static/js/lang/fr.json

@@ -27,5 +27,6 @@
 	"registerFormPassword": "Mot de passe",
 	"registerFormButton": "S'inscrire",
 	"registerAlreadyAccount": "Déjà un compte?",
-	"registerLogin": "Connexion"
+	"registerLogin": "Connexion",
+	"404WindowTitle": "Pas trouvé"
 }

frontend/static/js/views/PageNotFoundView.js

@@ -1,8 +1,9 @@
 import AbstractView from "./abstracts/AbstractView.js";
+import { lang } from '../index.js'
 
 export default class extends AbstractView {
     constructor(params) {
-        super(params, "Not Found");
+        super(params, lang.get('404WindowTitle', 'Not Found'));
     }
 
 	async getHtml() {