hunk.code_window:     const startNode = range.startContainer
       const startOffset = range.startOffset
       const point = this.getPoint(startNode, startOffset)
       const target = Selection.create({
         anchorKey: point.key,
         anchorOffset: point.offset,
         focusKey: point.key,
         focusOffset: point.offset,
  
hunk.labels: keep keep keep add keep keep keep keep keep
hunk.after_edit:     if (!point) return
  
hunk.file_path: src/components/content.js
hunk.type: add
file: 
  export default function (state) {
    const { document, selection } = state
    const texts = document.getTexts()
    const first = texts.first()
    const range = selection.merge({
      anchorKey: first.key,
      anchorOffset: 1,
      focusKey: first.key,
      focusOffset: 3
    })
  
    return state
      .transform()
      .splitBlockAtRange(range)
      .apply()
  }
  