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
```
}
    beginMarkedContent(tag) {
      this.markedContentStack.push({
        visible: true,
      });
    }
    beginMarkedContentProps(tag, properties) {
      if (tag === "OC") {
        this.markedContentStack.push({
          visible: this.optionalContentConfig.isVisible(properties),
        });
      } else {
        this.markedContentStack.push({
          visible: true,
        });
      }
      this.contentVisible = this.isContentVisible();
    }
    endMarkedContent() {
      this.markedContentStack.pop();
      this.contentVisible = this.isContentVisible();
    }
    
    beginCompat() {
      
    }
    endCompat() {