Moved the cimport openmp example out of the rst to put it in the examples directory.

docs/examples/userguide/parallelism/cimport_openmp.pyx

+from cython.parallel cimport parallel
+cimport openmp
+
+cdef int num_threads
+
+openmp.omp_set_dynamic(1)
+with nogil, parallel():
+    num_threads = openmp.omp_get_num_threads()
+    # ...

docs/src/userguide/parallelism.rst

@@ -212,17 +212,9 @@ whether it will simply break or whether it will return 2.
 
 Using OpenMP Functions
 ======================
-OpenMP functions can be used by cimporting ``openmp``::
+OpenMP functions can be used by cimporting ``openmp``:
 
-    from cython.parallel cimport parallel
-    cimport openmp
-
-    cdef int num_threads
-
-    openmp.omp_set_dynamic(1)
-    with nogil, parallel():
-        num_threads = openmp.omp_get_num_threads()
-        ...
+.. literalinclude:: ../../examples/userguide/parallelism/cimport_openmp.pyx
 
 .. rubric:: References