Fix problems

...tutorial/belajarbelajar/controller/LatihanController.java

...a/apap/tutorial/belajarbelajar/service/CourseService.java

...lajarbelajar/src/main/resources/templates/add-course.html

...lajarbelajar/src/main/resources/templates/add-failed.html

...arbelajar/src/main/resources/templates/delete-course.html

...belajar/src/main/resources/templates/deletion-failed.html

...belajar/src/main/resources/templates/fail-add-course.html

...ajar/src/main/resources/templates/fail-delete-course.html

...ar/src/main/resources/templates/fail-update-pengajar.html

.../src/main/resources/templates/failed-delete-pengajar.html

.../src/main/resources/templates/failed-update-pengajar.html

...ajar/src/main/resources/templates/form-update-course.html

...ar/src/main/resources/templates/form-update-pengajar.html

...jar/src/main/resources/templates/gagal-delete-course.html

...r/src/main/resources/templates/gagal-update-pengajar.html

...jarbelajar/src/main/resources/templates/handling-add.html

...belajar/src/main/resources/templates/handling-delete.html

...jar/belajarbelajar/src/main/resources/templates/home.html

...arbelajar/src/main/resources/templates/update-course.html

...belajar/src/main/resources/templates/update-pengajar.html