cs: klister: links to before and after case study

- fixes: haskellfoundation#93

Author: doyougnu

src/Case_Studies/klister.rst

@@ -14,11 +14,16 @@ of any system which is shortlived, has distinct phases of input and output, and
 maintains state. To diagnose the performance issues this case study uses
 :ref:`Heap Profiling <Heap Profiling Chapter>` with :ref:`Eventlog <EventLog
 Chapter>`, :ref:`Info Table Profiling <IPE Chapter>`, :ref:`TickyTicky <Ticky
-Chapter>` profiling. The optimizations are simply choosing better data
+Chapter>` profiling. The optimizations are trivial: choosing better data
 structures and closing memory leaks; any intermediate level Haskeller should be
 able to follow along. After reading this chapter, a reader should be able to
-spot inefficient data structure use by reading code, and utilize profiling
-techniques to diagnose memory performance issues and identify hot code.
+spot inefficient data structure use by reading code, and GHC's profiling tools
+to diagnose memory performance issues and identify hot code. To read through the
+code, `this commit
+<https://github.com/gelisam/klister/commit/33501b2233ce865407a8a3ca7c090457f3375442>`_
+is the result of the case study, and `this commit
+<https://github.com/gelisam/klister/tree/5aea4d2b9df8f6e9db276078570c1e1bd1306cd3>`_
+was the state of the klister code base that the tutorial starts with.
 
 The rest of the chapter is structured as follows. We introduce the |klister|
 interpreter and perform a performance minded code review. We then use the