* Corrected and cleaned up private-server.mdx
The guide didn't link to downloads for the server executables, had technically incorrect instructions for linux (linux users dont run server-mac(os)), and mac instructions erroneously guided users to download and use `server-mac` rather than `server-macos`.
While i was here, the instructions felt a bit rushed, so i cleaned some things up. Feel free to modify as you see fit
* Fix typo and add a code block to highlight the field to change
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Co-authored-by: Andrii Zadorozhnyi <andres99.dev@gmail.com>
