Add 'fr' to list of supported locales

src/invidious.cr

@@ -92,6 +92,7 @@ LOCALES = {
   "ar"    => load_locale("ar"),
   "de"    => load_locale("de"),
   "en-US" => load_locale("en-US"),
+  "fr"    => load_locale("fr"),
   "nb_NO" => load_locale("nb_NO"),
   "nl"    => load_locale("nl"),
   "pl"    => load_locale("pl"),