Changing the text for sustain markings

Staff.pedalSustainStrings can be used to set the text used for pedal down and up. Note that the only valid strings are those found in the list of pedal glyphs - the values used this snippet constitute an exhaustive list.

\version "2.24"

sustainNotes = { c4\sustainOn d e\sustainOff\sustainOn f\sustainOff }

\relative c' {
  \sustainNotes 
  \set Staff.pedalSustainStrings = #'("P" "P-" "-")
  \sustainNotes 
  \set Staff.pedalSustainStrings = #'("d" "de" "e")
  \sustainNotes 
  \set Staff.pedalSustainStrings = #'("M" "M-" "-")
  \sustainNotes 
  \set Staff.pedalSustainStrings = #'("Ped" "*Ped" "*")
  \sustainNotes 
}