1 character fix to make ob-haskell compatible with table outputs

[ParetoOptimalDev]

Just change the `[` and `]` to `(` and `)` respectively.

List of lists aren't parsed correctly by ob-haskell, but tuples of
tuples are.

That means this code change I just tested works:

(defun org-babel-haskell-var-to-haskell (var)
  "Convert an elisp value VAR into a haskell variable.
The elisp VAR is converted to a string of haskell source code
specifying a variable of the same value."
  (if (listp var)
      (concat "(" (mapconcat #'org-babel-haskell-var-to-haskell var ", ") ")")
    (format "%S" var)))

For something like:

name:tbl
#+begin_src sh
echo -e "1\t2\t3"
#+end_src

#+RESULTS:
| 1 | 2 | 3 |

#+begin_src haskell :var table=tbl
print table
#+end_src

#+RESULTS:
| 1 | 2 | 3 |

Whereas before it would not print the table out because it isn't parsed 
correctly.