Document the socket backend as a valid option

diff --git a/scm/lily.scm b/scm/lily.scm
index 9420744d64d34b68c0191911c8e8ea78e5d270d4..17063a9aef80eaccafd5cc31f49a083a6f534f28 100644 (file)
--- a/scm/lily.scm
+++ b/scm/lily.scm
@@ -40,7 +40,7 @@ and scale down result to prevent jaggies in
 PNG images.")
     (backend ps
 "Select backend.  Possible values: 'eps, 'null,
-'ps, 'scm, 'svg.")
+'ps, 'scm, 'socket, 'svg.")
     (check-internal-types #f
 "Check every property assignment for types.")
     (clip-systems #f