Changing text and spanner styles for text dynamics

The text used for crescendos and decrescendos can be changed by modifying the context properties crescendoText and decrescendoText.

The style of the spanner line can be changed by modifying the 'style property of DynamicTextSpanner. The default value is 'dashed-line, and other possible values include 'line, 'dotted-line and 'none.

\version "2.24.0"

\relative c'' {
  \set crescendoText = \markup { \italic { cresc. poco } }
  \set crescendoSpanner = #'text
  \override DynamicTextSpanner.style = #'dotted-line
  a2\< a
  a2 a
  a2 a
  a2 a\mf
}