fix(i18n): spanish `app_desc_short` (#806)

locales/es-ES.json

@@ -62,7 +62,7 @@
     "switch_account": "Cambiar cuenta",
     "vote": "Votar"
   },
-  "app_desc_short": "Un ágil cliente web de Mastodon",
+  "app_desc_short": "Un cliente web ágil para Mastodon",
   "app_logo": "Logotipo de Elk",
   "app_name": "Elk",
   "attachment": {