Directs displaying-grob-ancestry.ly to stderr (issue 5905052)

[PhilEHolmes]

Reviewers: dak, Graham Percival, Julien Rioux,

Message:
Please review

Description:
This is effectively a proof-of-concept patch to send the output from the
above snippet to stderr rather than stdout as at present.  As ever, it's
to reduce make doc clutter.  This patch should apply and work.  A real
patch will involve editing snippets/new and running makelsr.  I know
very little about Guile/scheme, so if there is a better way of doing
this I'd be happy to be told.

Please review this at http://codereview.appspot.com/5905052/

Affected files:
  M Documentation/snippets/displaying-grob-ancestry.ly


Index: Documentation/snippets/displaying-grob-ancestry.ly
diff --git a/Documentation/snippets/displaying-grob-ancestry.ly  
b/Documentation/snippets/displaying-grob-ancestry.ly
index  
3a20732484400e6096b21c79fcf5bc399a3c15c6..7523a965bb2a3c4b610a2843858a8b2cf28facea  
100644
--- a/Documentation/snippets/displaying-grob-ancestry.ly
+++ b/Documentation/snippets/displaying-grob-ancestry.ly
@@ -195,7 +195,7 @@ NoteHead X,Y: NoteColumn
     (format #f "~&")))

 #(define (display-ancestry grob)
-   (display
+   (format (current-error-port) "~a"
     (string-append
      (format #f "~3&~a~2%" (make-string 36 #\-))
      (format-ancestry (get-ancestry grob) 0)