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
```
let linearization = null;
    try {
      linearization = Linearization.create(this.stream);
    } catch (err) {
      if (err instanceof MissingDataException) {
        throw err;
      }
      info(err);
    }
    return shadow(this, "linearization", linearization);
  }
  get startXRef() {
    const stream = this.stream;
    let startXRef = 0;
    if (this.linearization) {
      
      stream.reset();
      if (find(stream, ENDOBJ_SIGNATURE)) {
        startXRef = stream.pos + 6 - stream.start;
      }
    } else {
      
      const step = 1024;
      const startXRefLength = STARTXREF_SIGNATURE.length;
      let found = false,
        pos = stream.end;