message: docs(core): correct insertBefore's description
  Update the description of `refChild`
  Based on
  PR Close
diff: @@ -157,7 +157,7 @@ export abstract class Renderer2 {
  * in the host element DOM.
  * @param parent The parent node.
  * @param newChild The new child nodes.
  - * @param refChild The existing child node that should precede the new node.
  + * @param refChild The existing child node before which `newChild` is inserted.
  */
  abstract insertBefore(parent: any, newChild: any, refChild: any): void;
  /**
  