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 (!src.url && !src.data && !src.range) {
      throw new Error(
        "Invalid parameter object: need either .data, .range or .url"
      );
    }
    source = src;
  }
  const params = Object.create(null);
  let rangeTransport = null,
    worker = null;
  for (const key in source) {
    const value = source[key];
    switch (key) {
      case "url":
        if (typeof window !== "undefined") {
          try {
            
            params[key] = new URL(value, window.location).href;
            continue;
          } catch (ex) {
            warn(`Cannot create valid URL: "${ex}".`);
          }
        } else if (typeof value === "string" || value instanceof URL) {
          params[key] = value.toString(); 
          continue;
        }
        throw new Error(
          "Invalid PDF url data: " +
            "either string or URL-object is expected in the url property."
        );