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
```
this.setModificationDate(parentItem.get("M"));
      this.data.modificationDate = this.modificationDate;
    }
    if (!parentItem.has("C")) {
      
      this.data.color = null;
    } else {
      this.setColor(parentItem.getArray("C"));
      this.data.color = this.color;
    }
    
    
    
    if (!this.viewable) {
      const parentFlags = parentItem.get("F");
      if (this._isViewable(parentFlags)) {
        this.setFlags(parentFlags);
      }
    }
    this.data.title = stringToPDFString(parentItem.get("T") || "");
    this.data.contents = stringToPDFString(parentItem.get("Contents") || "");
  }
}
class FreeTextAnnotation extends MarkupAnnotation {
  constructor(parameters) {
    super(parameters);
    this.data.annotationType = AnnotationType.FREETEXT;
  }
}
class LineAnnotation extends MarkupAnnotation {