Changing the default bar lines

Default bar lines can be changed when re-defined in a Score context.

\version "2.24"

% LSR https://lists.gnu.org/archive/html/lilypond-user/2014-03/msg00126.html
% LSR https://lists.gnu.org/archive/html/lilypond-user/2014-12/msg00189.html

\layout {
  \context {
    \Score
    %% Changing the defaults from engraver-init.ly
    measureBarType = "!"
    startRepeatBarType = "[|:"
    endRepeatBarType = ":|]"
    doubleRepeatBarType = ":|][|:"
  }
} 

{ 
  c'1
  \repeat volta 2 { c' c' }
  \repeat volta 2 { c' c' \alternative { \volta 1 { c' }
                                         \volta 2 { c' } } }
  \bar "|."
}