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.data.quadPoints === null) {
      return false;
    }
    if (this.flags === 0) {
      return false;
    }
    return this._isPrintable(this.flags);
  }
  /**
   * Set the contents.
   *
   * @public
   * @memberof Annotation
   * @param {string} contents - Text to display for the annotation or, if the
   *                            type of annotation does not display text, a
   *                            description of the annotation's contents
   */
  setContents(contents) {
    this.contents = stringToPDFString(contents || "");
  }
  /**
   * Set the modification date.
   *
   * @public
   * @memberof Annotation
   * @param {string} modificationDate - PDF date string that indicates when the
   *                                    annotation was last modified
   */
  setModificationDate(modificationDate) {