LSR changes for \textMark/\textEndMark

[Jean Abou Samra]

Harm,

As you can see from open MRs, I'm working on moving from \mark <markup>
to text marks in tests and documentation. Could you please apply the
following changes in LSR?

These snippets should have their doc tag removed because 
\textMark/\textEndMark
address limitations that they show how to work around:

- aligning-objects-created-with-the--mark-command, since \textMark and
  \textEndMark have a default alignment that should be the right thing
  in most cases (and !1641 adds a doc example on customizing the alignment
  anyway).

- printing-marks-at-the-end-of-a-line.ly

- creating-simultaneous-rehearsal-marks.ly

- 
how-to-print-two-rehearsal-marks-above-and-below-the-same-barline-method-{1,2}.ly

These 5 snippets should eventually be removed from LSR when it's
upgraded to 2.24.

Also, these snippets don't actually need \mark <markup>, should be
changed to use something else:

- wind-headword.ly: replace

      \once \override Score.RehearsalMark.self-alignment-X = #-1
      \once \override Score.RehearsalMark.break-align-symbols = 
#'(time-signature)
      \once \override Score.TimeSignature.break-align-anchor-alignment 
= #LEFT
      \once \override Score.RehearsalMark.padding = #4
      \mark \markup \large \bold {Moderato assai}

  with just

      \tempo \markup \large "Moderato assai"

- table-of-contents.ly: change \mark "A" to \mark \default.


I'll take care of the rest by moving snippets to new/ and changing
them to use \textMark/\textEndMark.

Thanks!

Jean