Polishing.

Reformat code. Make getAnnotatedHint non-nullable.

See #3230
Original pull request: #4339

src/main/asciidoc/reference/mongo-repositories.adoc

@@ -306,14 +306,15 @@ The `@Hint` annotation allows to override MongoDB's default index selection and
 ====
 [source,java]
 ----
-@Hint("lastname-idx") <1>
+@Hint("lastname-idx")                                          <1>
 List<Person> findByLastname(String lastname);
 
-@Query(value = "{ 'firstname' : ?0 }", hint="firstname-idx") <2>
+@Query(value = "{ 'firstname' : ?0 }", hint = "firstname-idx") <2>
 List<Person> findByFirstname(String firstname);
 ----
+
 <1> Use the index with name `lastname-idx`.
-<2> The `@Query` annotation defines the `hint` alias which is equivalent to explicitly adding the `@Hint` annotation.
+<2> The `@Query` annotation defines the `hint` alias which is equivalent to adding the `@Hint` annotation.
 ====
 
 [[mongodb.repositories.queries.update]]