[WIP] Update language recommendation to use languages instead of language

[Copilot]

• Update examples to use languages (plural) instead of language (singular)
• Update examples to use lower-case language names (e.g., go instead of Go)
• Update documentation to reflect the new recommendation
• Run tests to ensure changes don't break functionality
• Request code review

Original prompt

We now recommend you use languages not just language and the language is lower-case.

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