Add description to metadata output #3617

[shiver]

Just took a quick stab at issue #3617.

Is my interpretation of the requirements correct, and if so, would you prefer new tests or are the current alterations sufficient.

Thanks!

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @alexcrichton (or someone else) soon.

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[alexcrichton]

@bors: r+

Looks great to me, thanks!

[bors]

📌 Commit 7762949 has been approved by alexcrichton

[bors]

⌛ Testing commit 7762949 with merge 12648f8...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: alexcrichton
Pushing 12648f8 to master...