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
```
constructor(parameters) {
    super(parameters);
    this.data.annotationType = AnnotationType.POLYLINE;
    this.data.vertices = [];
    /
    /
    
    const rawVertices = parameters.dict.getArray("Vertices");
    if (!Array.isArray(rawVertices)) {
      return;
    }
    for (let i = 0, ii = rawVertices.length; i < ii; i += 2) {
      this.data.vertices.push({
        x: rawVertices[i],
        y: rawVertices[i + 1],
      });
    }
    if (!this.appearance) {
      
      const strokeColor = this.color
        ? Array.from(this.color).map(c => c / 255)
        : [0, 0, 0];
      const strokeAlpha = parameters.dict.get("CA");
      const borderWidth = this.borderStyle.width || 1,
        borderAdjust = 2 * borderWidth;