Fix syntax error in documentation.

docs/src/userguide/memoryviews.rst

@@ -114,9 +114,9 @@ starting at the second (index 1) and then skips every second (odd) row::
 
     cdef int[1:102:2,:] partial_view = exporting_object
 
-This also works conveniently as function arguments::
+This also works conveniently as function arguments:
 
-..  code-block:: cython
+.. code-block:: cython
 
     def process_3d_buffer(int[1:102:2,:] view not None):
         ...