POST /documents/{document_id}/convert

{
  "content": "# 标题\n\n正文\n\n- 列表项",
  "content_type": "markdown"
}

POST /documents/{document_id}/blocks/{block_id}/children?document_revision_id=-1

{
  "children": [...],
  "index": 0
}

{"block_type": 2, "text": {"elements": [{"text_run": {"content": "段落"}}]}}

{"block_type": 3, "heading1": {"elements": [{"text_run": {"content": "标题"}}]}}

{
  "block_type": 14,
  "code": {
    "style": {"language": 1},
    "elements": [{"text_run": {"content": "console.log('hello')"}}]
  }
}

{
  "block_type": 19,
  "callout": {
    "background_color": 1,
    "border_color": 1,
    "emoji_id": "bulb"
  },
  "children": [
    {"block_type": 2, "text": {"elements": [{"text_run": {"content": "提示内容"}}]}}
  ]
}

{
  "text_run": {
    "content": "样式文本",
    "text_element_style": {
      "bold": true,
      "italic": true,
      "strikethrough": true,
      "underline": true,
      "inline_code": true,
      "background_color": 1,
      "text_color": 1
    }
  }
}