Stop Documentation/ly-examples/orchestra.ly from redefining markup commands (issue 10431047)

[k-ohara5a5a]

> Removing the warnings is possible by removing the
> Axis_group_engraver from the MarkLine context definition,
> but this messes up the positions of the tempo marks.

You could keep the positioning and remove the warnings with
   \override MetronomeMark #'Y-offset  = #'()

The default has the tempo mark try to use side-position-interface, which
doesn't seem to work with no staff symbol.


https://codereview.appspot.com/10431047/