Explaining how to link mixed C/Rust binaries.

[adetaylor]

Discussed in rust-lang/rust#73632

[ehuss]

Thanks for the PR! In general, we want the reference to be more about the language, and less about the implementation. To that end, I think this content is better suited for the rustc book. In a sense, almost the entirety of this chapter should probably move, but I am uncertain how exactly that should be structured. So I'm a bit reluctant to continue down the path of adding more compiler-specific information. Maybe you would be interested in figuring out how to untangle this and figure out how to organize things?

[adetaylor]

Hi @ehuss, thanks for the comment. I understand this chapter is in a slightly odd status. I'm afraid I'm not likely to be the Untangler here, sorry! Shall I abandon this PR or can I convince you that it doesn't really make things worse?