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() {
      this._capability = createPromiseCapability();
      this._transport = null;
      this._worker = null;
      /**
       * Unique identifier for the document loading task.
       * @type {string}
       */
      this.docId = "d" + nextDocumentId++;
      /**
       * Whether the loading task is destroyed or not.
       * @type {boolean}
       */
      this.destroyed = false;
      /**
       * Callback to request a password if a wrong or no password was provided.
       * The callback receives two parameters: a function that should be called