Fix expansion of LLM

[markphip]

Code of Conduct

• I have read and agree to the GitHub Docs project's Code of Conduct

What article on docs.github.com is affected?

I noticed on the page Using Copilot's LLM for your agent that it expands LLM to mean "Language Learning Model" as opposed to "Large Language Model"

What part(s) of the article would you like to see updated?

I will submit a PR

Additional information

No response

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