update comment (#747)

eBook/14.2.md

@@ -267,7 +267,7 @@ func compute(ch chan int){
 
 func main(){
 	ch := make(chan int) 	// allocate a channel.
-	go compute(ch)		// stat something in a goroutines
+	go compute(ch)		// start something in a goroutines
 	doSomethingElseForAWhile()
 	result := <- ch
 }