Add origin of "rust" name to project FAQ

[joliv]

See https://www.reddit.com/r/rust/comments/27jvdt/internet_archaeology_the_definitive_endall_source/

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @pcwalton (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 The way Github handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed.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.

[japaric]

cc @steveklabnik @brson

(btw, a similar PR has been rejected before see #14896 for the reasons)

[joliv]

Ah, my bad, didn't see that rejected commit. Is this different given that it's sourced, or do we still want to maintain the mystique here?

[emberian]

Closing for the same reasons as the other PR.