Add "cresc."/"dim." to text line "secret identity" of hairpins

With the new implementation of #74171: Implement "cresc." dashed line as alternative to hairpin, a "crescendo line" can be converted into a "crescendo hairpin" using just the Inspector (and back again), but the reverse is not true. It would be a slight ease-of-use improvement for the hairpins in the palette to already have "cresc." and "dim." secretly embedded in their text line aspect, and perhaps even add this to pre-existing hairpins on import.