DOCS: add index items for displayMusic function

diff --git a/Documentation/user/programming-interface.itely b/Documentation/user/programming-interface.itely
index b7fdd8ecfc18c2b7bb6dbdf0e160a0c4a636c8b7..69397cfb78f6ee61d0a25d9c9e84d388562b4d00 100644 (file)
--- a/Documentation/user/programming-interface.itely
+++ b/Documentation/user/programming-interface.itely
@@ -466,6 +466,9 @@ to create complicated music functions.
 @subsection Displaying music expressions
 
 @cindex internal storage
+@cindex displaying music expressions
+@cindex internal representation, displaying
+@cindex displayMusic
 @funindex \displayMusic
 
 When writing a music function it is often instructive to inspect how