Method prependSibling

external/.scrollLibs.js:17075–17077

(line, subparticles)

    return this
  }
  prependSibling(line, subparticles) {
    return this.parent.insertLineAndSubparticles(line, subparticles, this.index)
  }
  appendSibling(line, subparticles) {
    return this.parent.insertLineAndSubparticles(line, subparticles, this.index + 1)
  }