Update and expand line breaks FAQ

[mattt]

Resolves #6

[mtsknn]

Off-topic question, if you don't mind:

I find your way of using reference links interesting, in a good way.

• Only reference links are used.
• Link labels are simple (short, all lowercase, no spaces).
• All link reference definitions are at the end of the document, sorted by link labels.

Do you know any resources related to this? Kinda like the sembr spec, though I don't know if these simple practices warrant a spec.