Add license qualifier documentation to code search syntax article

[PreciselyAlyss]

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?

https://docs.github.com/en/search-github/github-code-search/understanding-github-code-search-syntax

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

Addition of the license qualifier to the content of the page. This is currently undocumented on the code search syntax article, but present on the licensing a repository article. https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/licensing-a-repository#searching-github-by-license-type

Additional information

No response

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