faq: mention go vet in "What happens with closures running as goroutines?"
faq: mention go vet in "What happens with closures running as goroutines?"

R=r
CC=golang-dev
http://codereview.appspot.com/6822111

Committer: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang