Clarified the cons/conj list return type

While reading through the article, I went looking for clarification of cons/conj.  I ran into a thread that described the two functions as expanded to:

conj(oin items)
cons(truct a sequence)

And after doing some poking around in the repl, it is true that the returned classes from conj and cons are not the same:

```
user=> (def stooges (list "Moe" "Larry" "Curly"))
#'user/stooges
user=> (class (conj stooges "Shemp"))
clojure.lang.PersistentList
user=> (class (cons "Shemp" stooges))
clojure.lang.Cons
```

I am a Clojure newb though, and so I don't know if a Cons is more similar to a PersistentList than a LazySeq type. Meaning, I don't know enough of clojure to know if this change is more confusing than helpful.  If a Cons quacks like a List, then this is probably more confusing. But, saying that both return a list isn't quite true (but it might be true enough).