message: Add an 'InsertPosition' string literal type, to be used by the element insertion methods (insertAdjacentElement / insertAdjacentHTML / insertAdjacentText)
diff: "signatures": [
  "new(data?: string): Text"
  ]
  + },
  + {
  + "kind": "typedef",
  + "name": "InsertPosition",
  + "flavor": "Web",
  + "type": "\"beforebegin\" | \"afterbegin\" | \"beforeend\" | \"afterend\""
  + },
  + {
  + "kind": "method",
  + "interface": "Element",
  + "name": "insertAdjacentElement",
  + "signatures": ["insertAdjacentElement(position: InsertPosition, insertedElement: Element): Element | null"]
  + },
  + {
  + "kind": "method",
  + "interface": "Element",
  + "name": "insertAdjacentHTML",
  + "signatures": ["insertAdjacentHTML(where: InsertPosition, html: string): void"]
  + },
  + {
  + "kind": "method",
  + "interface": "Element",
  + "name": "insertAdjacentText",
  + "signatures": ["insertAdjacentText(where: InsertPosition, text: string): void"]
  }
  ]
  