Polishing.

Add missing package-info.

See #4248
Original pull request: #4249

Author: mp911de

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/repository/aot/package-info.java

@@ -0,0 +1,5 @@
+/**
+ * Ahead-Of-Time processors for MongoDB repositories.
+ */
+@org.springframework.lang.NonNullApi
+package org.springframework.data.mongodb.repository.aot;