docs(examples): fix two stale example comments (#3877)

## Summary

- `examples/parsing_tools_stream.py:27`: the comment credits
`.parse_stream()` for the tool-call deserialization, but no such method
exists in the SDK (`grep -rn parse_stream src/openai` → 0) — the
wrapping comes from `pydantic_function_tool(...)`. The comment drifted
when the example moved from `client.beta.chat.completions.stream`.
- `examples/realtime/audio_util.py:16`: `CHUNK_LENGTH_S = 0.05 # 100ms`
— 0.05 s is 50 ms (1200 frames at the module's 24 kHz rate). Comment
corrected.

Comment-only changes in examples/.

## Checklist

- [x] I understand that this repository is auto-generated and my pull
request may not be merged

Co-authored-by: Marcus Wood <marcuswood@openai.com>