fix: 修复学生不能正常获取课件的问题

src/main/java/nju/seec/helper/dao/SlideDAO.java

@@ -69,7 +69,7 @@ public interface SlideDAO extends JpaRepository<Slide, Integer> {
      */
     @Query("select s from Slide s " +
             "where s.courseId=?1 " +
-            "and s.state not in ?2" +
+            "and s.state not in ?2 " +
             "and s.name like concat('%',?3,'%') " +
             "and s.deleteAt=0")
     Page<Slide> findByCourseIdAndStateNotInAndNameContains(Integer courseId, Set<SlideState> exclusiveStates, String key, Pageable pageable);