when advancing to next note in lyrics input mode, auto-select existing syllable if present
When entering lyrics and advancing to the next note, if that note already has lyrics, MuseScore currently places the cursor at the end of the existing syllable, ready to append additional text. However, in most cases, a user will be attempting to overwrite existing lyrics. Therefore, it would make the most sense to have existing syllables automatically selected so that typing will replace them. This is the same way that Finale handles this.