Make arguments like Context.GrobName accessible as symbol lists

Documentation/snippets/adding-orchestral-cues-to-a-vocal-score.ly

 % DO NOT EDIT this file manually; it is automatically
 % generated from Documentation/snippets/new
 % Make any changes in Documentation/snippets/new/
 % and then run scripts/auxiliar/makelsr.py
 %
 % This file is in the public domain.
 %% Note: this file works from version 2.16.0
-\version "2.16.0"
+\version "2.17.6"
 
 \header {
   lsrtags = "staff-notation, vocal-music"
 
   texidoc = "
 This shows one approach to simplify adding many orchestral cues to the
 piano reduction in a vocal score.  The music function @code{\\cueWhile}
 takes four arguments: the music from which the cue is to be taken, as
 defined by @code{\\addQuote}, the name to be inserted before the cue
 notes, then either @code{#UP} or @code{#DOWN} to specify either
 @code{\\voiceOne} with the name above the staff or @code{\\voiceTwo}
 with the name below the staff, and finally the piano music in parallel
 with which the cue notes are to appear.  The name of the cued
 instrument is positioned to the left of the cued notes. Many passages
 can be cued, but they cannot overlap each other in time.
 
 "
   doctitle = "Adding orchestral cues to a vocal score"
 } % begin verbatim
 
 
 cueWhile =
 #(define-music-function
    (parser location instrument name dir music)
    (string? string? ly:dir? ly:music?)
    #{
      \cueDuring $instrument #dir {
-       \once \override TextScript #'self-alignment-X = #RIGHT
-       \once \override TextScript #'direction = $dir
+       \once \override TextScript.self-alignment-X = #RIGHT
+       \once \override TextScript.direction = $dir
        <>-\markup { \tiny #name }
        $music
      }
    #})
 
 flute = \relative c'' {
   \transposition c'
   s4 s4 e g
 }
 \addQuote "flute" { \flute }
@@ skipping 31 matching lines @@
           \pianoRH
         }
       }
       \new Staff {
         \clef "bass"
         \pianoLH
       }
     >>
   >>
 }