[mcp-servers] Switch the header example to something more likely

[julien-c]

i expect most keys will be passed as Authorization: Bearer headers, so this would make the doc simpler to understand

[isidorn]

Thank you. Makes sense. Though let's see if @digitarald or @connor4312 have any feedback.

[connor4312]

I'm fine keeping the example header as API_KEY. Specifically for authorization, newly implemented servers should tend to use MCP's Authorization capability rather than explicit Authorization headers.

[digitarald]

Thanks for contributing more realistic docs.

I agree with Connor's point, to not showcase auth via keys; and we should even call it out for this line as best practice.

[ntrogh]

@julien-closing this PR, given the above feedback. I'll update the docs to include additional guidance about authorization.

[julien-c]

that works, thanks for reviewing!