Fix typo in chat template example

[EricWinsorDSIT]

What does this PR do?

This PR fixes a typo in the first example jinja chat template. The template was missing a ' mark so attempting to use it in code causes a jinja syntax error.

Before submitting

• [ x ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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• Did you make sure to update the documentation with your changes? Here are the
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  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

@stevhliu

[stevhliu]

Great catch, thanks!

[HuggingFaceDocBuilderDev]

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