funclang series3: Added comments for 'nth' fucntion.

funclang-taddeus/series3/ass7.ml

@@ -2,7 +2,8 @@ open List
 
 (* 1 *)
 let rec nth l n =
-    (*  *)
+    (* Walk through the list recursively, subtracting 1 off n each time and
+     * matching it with 0 to check of the nth element has been reached yet *)
     match n with
     | 0 -> hd l
     | i when i > 0 && i < (length l) -> nth (tl l) (i - 1)