Fix code highlights in README.rst

README.rst

@@ -47,16 +47,14 @@ an infinite number of times!  Instead, let's put Kapow! into action.
 With Kapow! you just need to create a ``.pow`` file named ``backups.pow`` that
 contains:
 
-```Shell
+.. code-block:: sh
     kapow route add /backups \
         -c 'cloudx storage ls /backups | grep $(kapow get /request/params/query) | kapow set /response/body'
-```
 
 and execute it in the remote host with the command:
 
-```Shell
+.. code-block:: sh
     kapow server backups.pow
-```
 
 and that's it.  Done.  You have a web server that people can use to request
 their backups every time they need only by invoking the URL