Expose language detection in features

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>

lib/pleroma/web/mastodon_api/views/instance_view.ex

@@ -145,7 +145,10 @@ defmodule Pleroma.Web.MastodonAPI.InstanceView do
       end,
       "pleroma:get:main/ostatus",
       "pleroma:group_actors",
-      "pleroma:bookmark_folders"
+      "pleroma:bookmark_folders",
+      if Config.get([Pleroma.Language.LanguageDetector, :provider]) do
+        "pleroma:language_detection"
+      end
     ]
     |> Enum.filter(& &1)
   end