message: Fix apidoc syntax
diff: @@ -482,7 +482,7 @@ export class CourseController {
  * @apiParam {Object} data Data (with access key).
  * @apiParam {IUser} currentUser Currently logged in user.
  *
  - * @apiSuccess {{}} result Empty object.
  + * @apiSuccess {Object} result Empty object.
  *
  * @apiSuccessExample {json} Success-Response:
  * {}
  @@ -533,7 +533,7 @@ export class CourseController {
  * @apiParam {Object} data Body.
  * @apiParam {IUser} currentUser Currently logged in user.
  *
  - * @apiSuccess {{}} result Empty object.
  + * @apiSuccess {Object} result Empty object.
  *
  * @apiSuccessExample {json} Success-Response:
  * {}
  @@ -653,7 +653,7 @@ export class CourseController {
  * @apiParam {String} id Course ID.
  * @apiParam {IUser} currentUser Currently logged in user.
  *
  - * @apiSuccess {{}} result Empty object.
  + * @apiSuccess {Object} result Empty object.
  *
  * @apiSuccessExample {json} Success-Response:
  * {}
  