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
```
pointsArray = [
        [
          { x: this.rectangle[0], y: this.rectangle[3] },
          { x: this.rectangle[2], y: this.rectangle[3] },
          { x: this.rectangle[0], y: this.rectangle[1] },
          { x: this.rectangle[2], y: this.rectangle[1] },
        ],
      ];
    }
    for (const points of pointsArray) {
      const [mX, MX, mY, MY] = pointsCallback(buffer, points);
      minX = Math.min(minX, mX);
      maxX = Math.max(maxX, MX);
      minY = Math.min(minY, mY);
      maxY = Math.max(maxY, MY);
    }
    buffer.push("Q");
    const formDict = new Dict(xref);
    const appearanceStreamDict = new Dict(xref);
    appearanceStreamDict.set("Subtype", Name.get("Form"));
    const appearanceStream = new StringStream(buffer.join(" "));
    appearanceStream.dict = appearanceStreamDict;
    formDict.set("Fm0", appearanceStream);
    const gsDict = new Dict(xref);
    if (blendMode) {
      gsDict.set("BM", Name.get(blendMode));
    }
    if (typeof strokeAlpha === "number") {
      gsDict.set("CA", strokeAlpha);
    }