Changed a comment to make it more meaningful.

docs/examples/tutorial/clibraries/queue3.pyx

@@ -39,7 +39,7 @@ cdef class Queue:
 
     cdef extend_ints(self, int* values, size_t count):
         cdef int value
-        for value in values[:count]:  # It is possible to slice pointers in Cython.
+        for value in values[:count]:  # Slicing pointer to limit the iteration boundaries.
             self.append(value)
 
     cpdef int peek(self) except? -1:

docs/src/tutorial/clibraries.rst

@@ -343,7 +343,7 @@ Adding an ``extend()`` method should now be straight forward::
         """Append all ints to the queue.
         """
         cdef int value
-        for value in values[:count]:  # It is possible to slice pointers in Cython.
+        for value in values[:count]:  # Slicing pointer to limit the iteration boundaries.
             self.append(value)
 
 This becomes handy when reading values from a C array, for example.