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
```
if (ref && !catalog.pageKidsCountCache.has(ref)) {
            catalog.pageKidsCountCache.put(ref, 1); 
          }
          return [obj, ref];
        }
        throw new FormatError(
          "The Linearization dictionary doesn't point " +
            "to a valid Page dictionary."
        );
      })
      .catch(reason => {
        info(reason);
        return catalog.getPageDict(pageIndex);
      });
  }
  getPage(pageIndex) {
    if (this._pagePromises[pageIndex] !== undefined) {
      return this._pagePromises[pageIndex];
    }
    const { catalog, linearization } = this;
    if (this.xfaFactory) {
      return Promise.resolve(
        new Page({
          pdfManager: this.pdfManager,
          xref: this.xref,
          pageIndex,
          pageDict: Dict.empty,
          ref: null,
          globalIdFactory: this._globalIdFactory,
          fontCache: catalog.fontCache,