Update core/src/main/java/com/scalar/db/api/AuthAdmin.java

Co-authored-by: Toshihiro Suzuki <[email protected]>

Author: komamitsu

core/src/main/java/com/scalar/db/api/AuthAdmin.java

@@ -397,6 +397,7 @@ default void revokePrivilegeFromRole(
     throw new UnsupportedOperationException(CoreError.AUTH_NOT_ENABLED.buildMessage());
   }
 
+  /** Represents a user. */
   interface User {
     String getName();