Make arguments like Context.GrobName accessible as symbol lists

Documentation/snippets/controlling-tuplet-bracket-visibility.ly

 %% DO NOT EDIT this file manually; it is automatically
 %% generated from LSR http://lsr.dsi.unimi.it
 %% Make any changes in LSR itself, or in Documentation/snippets/new/ ,
 %% and then run scripts/auxiliar/makelsr.py
 %%
 %% This file is in the public domain.
-\version "2.17.5"
+\version "2.17.6"
 
 \header {
   lsrtags = "rhythms, tweaks-and-overrides"
 
   texidoc = "
 The default behavior of tuplet-bracket visibility is to print a bracket
 unless there is a beam of the same length as the tuplet. To control the
 visibility of tuplet brackets, set the property
 @code{'bracket-visibility} to either @code{#t} (always print a
 bracket), @code{#f} (never print a bracket) or @code{#'if-no-beam}
 (only print a bracket if there is no beam).
 
 "
   doctitle = "Controlling tuplet bracket visibility"
 } % begin verbatim
 
 
 music = \relative c'' {
   \times 2/3 { c16[ d e } f8]
   \times 2/3 { c8 d e }
   \times 2/3 { c4 d e }
 }
 
 \new Voice {
   \relative c' {
     << \music s4^"default" >>
-    \override TupletBracket bracket-visibility = #'if-no-beam
+    \override TupletBracket.bracket-visibility = #'if-no-beam
     << \music s4^"'if-no-beam" >>
-    \override TupletBracket bracket-visibility = ##t
+    \override TupletBracket.bracket-visibility = ##t
     << \music s4^"#t" >>
-    \override TupletBracket bracket-visibility = ##f
+    \override TupletBracket.bracket-visibility = ##f
     << \music s4^"#f" >>
   }
 }