Add more languages

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/utils/i18n.ts

@@ -2,12 +2,13 @@ import Vue from 'vue';
 import VueI18n from 'vue-i18n';
 import messages from '@/i18n/index';
 
-const language = (window.navigator as any).userLanguage || window.navigator.language;
+const language = ((window.navigator as any).userLanguage || window.navigator.language).replace(/-/, '_');
+const locale = messages.hasOwnProperty(language) ? language : language.split('-')[0];
 
 Vue.use(VueI18n);
 
 export const i18n = new VueI18n({
-  locale: language.split('-')[0], // set locale
+  locale, // set locale
   messages, // set locale messages
   fallbackLocale: 'en_US',
 });