add sentry middleware doc link in comment

httpserver/routes.go

@@ -42,6 +42,8 @@ func (s *server) routes() {
 	// this adds a sentry reporting middleware if and only if
 	// sentry is enabled via setting of SENTRY_DSN in env.
 	if s.sentryEnabled {
+		// Options docs at
+		// https://docs.sentry.io/platforms/go/guides/http/
 		sentryHandler := sentryhttp.New(sentryhttp.Options{})
 		s.router.Use(sentryHandler.Handle)
 	}