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
```
return this.pdfManager.ensure(this, "content").then(content => {
      if (content instanceof BaseStream) {
        return content;
      }
      if (Array.isArray(content)) {
        return new StreamsSequenceStream(content);
      }
      
      return new NullStream();
    });
  }
  get xfaData() {
    if (this.xfaFactory) {
      return shadow(this, "xfaData", {
        bbox: this.xfaFactory.getBoundingBox(this.pageIndex),
      });
    }
    return shadow(this, "xfaData", null);
  }
  save(handler, task, annotationStorage) {