Minor fixes in code documentation

irlc/ex05/direct.py

...sts/unitgrade_data/BrachistochroneConstrainedQuestion.pkl

irlc/tests/unitgrade_data/BrachistochroneQuestion.pkl

irlc/tests/unitgrade_data/CartpoleCostQuestion.pkl

irlc/tests/unitgrade_data/CartpoleTimeQuestion.pkl

irlc/tests/unitgrade_data/DirectAgentPendulum.pkl

irlc/tests/unitgrade_data/DirectMethods.pkl

irlc/tests/unitgrade_data/DirectSolverQuestion.pkl

irlc/tests/unitgrade_data/Exam5InventoryEvaluation.pkl

irlc/tests/unitgrade_data/Exam6Toy2d.pkl

irlc/tests/unitgrade_data/ExamQuestion7FlowersStore.pkl

irlc/tests/unitgrade_data/PendulumQuestion.pkl

irlc/tests/unitgrade_data/Problem1BobsFriend.pkl

irlc/tests/unitgrade_data/Problem1DiscreteKuromoto.pkl

irlc/tests/unitgrade_data/Problem1Kuramoto.pkl

irlc/tests/unitgrade_data/Problem2BobsPolicy.pkl

irlc/tests/unitgrade_data/Problem2DeterministicDP.pkl

irlc/tests/unitgrade_data/Problem2DeterministicInventory.pkl

.../unitgrade_data/Problem3InventoryInventoryEnvironment.pkl

irlc/tests/unitgrade_data/Problem3PID.pkl