Fix typo.

examples/tree_of_list.mlw

@@ -43,7 +43,7 @@ module TreeOfList
   let tree_of_list (l: list elt) : tree elt
     ensures { inorder result = l }
     ensures { size result > 0 -> let h = height result in
--                power 2 (h-1) <= size result < power 2 h }
+                power 2 (h-1) <= size result < power 2 h }
   =
     let t, l = tree_of_list_aux (length l) l in
     assert { l = Nil };