Configuration:
- PDF.js version: 2.0.550

Steps to reproduce the problem:
1. Render document in SVG mode `renderMode="svg"`

What is the expected behavior? (add screenshot)
Rendering annotations same way as they rendered on canvas

What went wrong? (add screenshot)
```
Warning: Unimplemented operator beginAnnotations
Warning: Unimplemented operator endAnnotations
```
if (!this._annotationsPromise || this._annotationsIntent !== intent) {
      this._annotationsPromise = this._transport.getAnnotations(
        this._pageIndex,
        intent
      );
      this._annotationsIntent = intent;
    }
    return this._annotationsPromise;
  }
  /**
   * @returns {Promise<Object>} A promise that is resolved with an
   *   {Object} with JS actions.
   */
  getJSActions() {
    return (this._jsActionsPromise ||= this._transport.getPageJSActions(
      this._pageIndex
    ));
  }
  /**
   * @returns {Promise<Object | null>} A promise that is resolved with
   *   an {Object} with a fake DOM object (a tree structure where elements
   *   are {Object} with a name, attributes (class, style, ...), value and
   *   children, very similar to a HTML DOM tree), or `null` if no XFA exists.
   */
  async getXfa() {