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 (!this.contentVisible) {
        return;
      }
      this.save();
      const currentCtx = this.ctx;
      
      
      
      
      
      
      
      
      
      
      
      
      
      if (!group.isolated) {
        info("TODO: Support non-isolated groups.");
      }
      
      
      if (group.knockout) {
        warn("Knockout groups not supported.");
      }