Update URL of the fingertree paper.

Author: foxik

Data/Sequence.hs

@@ -40,7 +40,7 @@
 --    * Ralf Hinze and Ross Paterson,
 --      \"Finger trees: a simple general-purpose data structure\",
 --      /Journal of Functional Programming/ 16:2 (2006) pp 197-217.
---      <http://www.soi.city.ac.uk/~ross/papers/FingerTree.html>
+--      <http://staff.city.ac.uk/~ross/papers/FingerTree.html>
 --
 -- /Note/: Many of these operations have the same names as similar
 -- operations on lists in the "Prelude".  The ambiguity may be resolved