Fix comment in manufactured solution configs

Author: xylar

polaris/ocean/tasks/manufactured_solution/manufactured_solution.cfg

@@ -77,8 +77,9 @@ refinement_factors_time = 1., 0.5, 0.25
 [convergence_forward]
 
 # time integrator
-#  mpas-ocean: {'split_explicit', 'RK4'}
-#  omega: {'Forward-Backward', 'RungeKutta4', 'RungeKutta2'}
+#  either: {'RK4'}
+#  mpas-ocean: {'split_explicit'}
+#  omega: {'Forward-Backward', 'RungeKutta2'}
 time_integrator = RK4
 
 # RK4 time step per resolution (s/km), since dt is proportional to resolution