Auto merge of #8978 - joshtriplett:faq-clarification, r=Eh2406
Auto merge of #8978 - joshtriplett:faq-clarification, r=Eh2406

Clarify FAQ entry wording about lockfiles

I received a report that this FAQ entry (and in particular the wording
"across whatever machine") generated some confusion. Reword the FAQ
entry for clarity.

nipunn1313/cargo,rust-lang/cargo,eminence/cargo,rustyhorde/cargo,eminence/cargo,nipunn1313/cargo,nipunn1313/cargo,nipunn1313/cargo,rust-lang/cargo,rustyhorde/cargo,rustyhorde/cargo,rust-lang/cargo,rustyhorde/cargo,rust-lang/cargo,eminence/cargo,eminence/cargo