Update docstring w missing line (#1493)

Author: kt474

qiskit_ibm_runtime/__init__.py

@@ -60,6 +60,8 @@
     qc.cx(qr[0], qr[1])
     qc.measure(qr, cr)
 
+    pm = generate_preset_pass_manager(target=backend.target, optimization_level=1)
+
     backend = service.least_busy(operational=True, simulator=False)
     bell_isa_circuit = pm.run(qc)
     psi_isa_circuit = pm.run(psi)