Add Ido (io) translation (#2202)

* Add Ido (io) translation

* Fix mastodon.jsx for io reference

There is no react-intl support for io. Removed the references.

app/assets/javascripts/components/locales/index.jsx

@@ -3,6 +3,7 @@ import de from './de';
 import es from './es';
 import hr from './hr';
 import hu from './hu';
+import io from './io';
 import it from './it';
 import fr from './fr';
 import nl from './nl';
@@ -25,6 +26,7 @@ const locales = {
   es,
   hr,
   hu,
+  io,
   it,
   fr,
   nl,