Forcing measure width to adapt to MetronomeMark's width

By default, metronome marks do not influence horizontal spacing.

This can be solved through a simple override, as shown in the second half of the example.

\version "2.24.0"

example = {
  \tempo "Allegro"
  R1*6
  \tempo "Rall."
  R1*2
  \tempo "A tempo"
  R1*8
}

{
  \compressMMRests {
    \example
    R1
    R1
    \override Score.MetronomeMark.extra-spacing-width = #'(-3 . 0)
    \example
  }
}