This pull request makes a minor adjustment to how token responses are handled in the articles/openai-harmony.md documentation. The change ensures that the last two tokens (typically stop tokens) are excluded before parsing the response, which helps prevent parsing errors.

• Documentation update: Demonstrates slicing the last two tokens off the tokens list before passing it to parse_messages_from_completion_tokens, ensuring stop tokens are not included in the parsed response.## Summary

Briefly describe the changes and the goal of this PR. Make sure the PR title summarizes the changes effectively.

Motivation

Why are these changes necessary? How do they improve the cookbook?

Example is throwing an HarmonyError

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