Configs link

[serejkus]

The book in "hello-world" tells that there are configs for some programs and gives a link to main repo's src/etc. Actually, these configs moved to separate repos some days ago. This PR adds a markdown file with links and moves "hello-world" link about editors to point directly to this new file.

[rust-highfive]

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

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. The way Github handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see CONTRIBUTING.md for more information.

[serejkus]

And
r? @steveklabnik

[steveklabnik]

Hmm, interesting. I wouldn't have thought of this approach, but since src/etc is kind of a junk drawer, I think it's fine. Thanks!

[steveklabnik]

@bors: r+ 336dd6c rollup