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.params = params;
      this.objs = objs;
      this.commonObjs = commonObjs;
      this.operatorListIdx = null;
      this.operatorList = operatorList;
      this._pageIndex = pageIndex;
      this.canvasFactory = canvasFactory;
      this._pdfBug = pdfBug;
      this.running = false;
      this.graphicsReadyCallback = null;
      this.graphicsReady = false;
      this._useRequestAnimationFrame =
        useRequestAnimationFrame === true && typeof window !== "undefined";
      this.cancelled = false;
      this.capability = createPromiseCapability();
      this.task = new RenderTask(this);
      
      this._cancelBound = this.cancel.bind(this);
      this._continueBound = this._continue.bind(this);
      this._scheduleNextBound = this._scheduleNext.bind(this);
      this._nextBound = this._next.bind(this);
      this._canvas = params.canvasContext.canvas;
    }
    get completed() {
      return this.capability.promise.catch(function () {
        
        
      });
    }
    initializeGraphics({ transparency = false, optionalContentConfig }) {