Added @knownissue for cross staffs and autobeaming (issue4440041)

[pkx166h]

Reviewers: ,

Message:
This is in response to Mike's last entry

http://code.google.com/p/lilypond/issues/detail?id=1612





Please review this at http://codereview.appspot.com/4440041/

Affected files:
  M Documentation/notation/rhythms.itely


Index: Documentation/notation/rhythms.itely
diff --git a/Documentation/notation/rhythms.itely  
b/Documentation/notation/rhythms.itely
index  
794185425782e521eeb1fa7c48d7cb3b1079f9c4..4879825989e3f38d6c614ded87f27d0fcde5dc56  
100644
--- a/Documentation/notation/rhythms.itely
+++ b/Documentation/notation/rhythms.itely
@@ -1922,6 +1922,29 @@ Internals Reference:
 @rinternals{beam-interface},
 @rinternals{unbreakable-spanner-interface}.

address@hidden
+
+Using @code{\change Staff} with automatic beaming may cause excessively
+long stems.
+
address@hidden,verbatim]
+<<
+  \new Staff {
+    \clef treble
+    \time 2/4
+    b'8 b' b' b' |
+    \change Staff = "bottom"
+  }
+  \new Staff = "bottom" {
+    \clef bass
+    c8 c c c |
+  }
+>>
address@hidden lilypond
+
+In this case use @ref{Manual beams}.
+
+
 @node Setting automatic beam behavior
 @unnumberedsubsubsec Setting automatic beam behavior