Refactor get/set_property to take the item as first argument

lily/sustain-pedal.cc

 /*
   This file is part of LilyPond, the GNU music typesetter.
 
   Copyright (C) 2000--2020 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
   LilyPond is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
@@ skipping 35 matching lines @@
   DECLARE_SCHEME_CALLBACK (print, (SCM));
 };
 
 MAKE_SCHEME_CALLBACK (Sustain_pedal, print, 1);
 SCM
 Sustain_pedal::print (SCM smob)
 {
   Grob *e = unsmob<Grob> (smob);
 
   Stencil mol;
-  SCM glyph = e->get_property ("text");
+  SCM glyph = get_property (e, "text");
   if (!scm_is_string (glyph))
     return mol.smobbed_copy ();
 
   string text = ly_scm2string (glyph);
 
   for (ssize i = 0; i < text.length (); i++)
     {
       string idx ("pedal.");
       if (text.substr (i, 3) == "Ped")
         {
           idx += "Ped";
           i += 2;
         }
       else
         idx += string (&text.c_str ()[i], 1);
       Stencil m = Font_interface::get_default_font (e)->find_by_name (idx);
       if (!m.is_empty ())
         mol.add_at_edge (X_AXIS, RIGHT, m, 0);
     }
 
   return mol.smobbed_copy ();
 }