Fix minor nitpick in the FAQ

[ghost]

Closes #657

Changed only en-US/faq.md

ru-RU/faq.md is empty so left it as it is.

1. fr/faq.md, zh-CN/faq.md and pt-BR/faq.md are not yet translated to the respective languages, so left them as it is. Should i modify them as well?
2. In ko-KR/faq.md, only the hyperlink needs changing should i change the hyperlink or leave it as it is?

[rust-highfive]

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 Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed.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

[alilleybrinker]

I'm actually not sure what the policy is for updating the translations. As I see it, there are a few potential policy options:

• Ping users providing translations when pages are updated. Don't stall merges while awaiting translation.
• Require updates to not-yet-translated pages (like the FAQ is in many of the translations), until the translation actually begins, at which point they are maintained separately.

Honestly, the FAQ is a tough thing to keep current in the translations, as (unlike much of the site) it is something we should generally expect to change and grow with decent regularity. It may be worthwhile to break the FAQ out in some way, perhaps as part of the Rust bookshelf idea that @steveklabnik has proposed. I'm really not sure what the right answer is here.

[steveklabnik]

I am not 100% sure what's right here either; let's discuss it in that issue, and in the meantime, merge this. Thanks!