DEV: Add default Accept-Language to FinalDestination requests (#13817)

Not specifying an `Accept-Language` should be equivalent to specifying an `Accept-Language` of `*`, however some webservers seem to prefer it if we are explicit about being able to handle a response of content in any language.

lib/final_destination.rb

@@ -89,6 +89,7 @@ class FinalDestination
     result = {
       "User-Agent" => @user_agent,
       "Accept" => "*/*",
+      "Accept-Language" => "*",
       "Host" => @uri.hostname
     }