Fix typo in Query Methods documentation.

Closes #1064

src/main/asciidoc/jdbc.adoc

@@ -470,7 +470,7 @@ interface PersonRepository extends PagingAndSortingRepository<Person, String> {
   Stream<Person> streamByLastname(String lastname);                                     <8>
 }
 ----
-<1> The method shows a query for all people with the given `lastname`.
+<1> The method shows a query for all people with the given `firstname`.
 The query is derived by parsing the method name for constraints that can be concatenated with `And` and `Or`.
 Thus, the method name results in a query expression of `SELECT … FROM person WHERE firstname = :firstname`.
 <2> Use `Pageable` to pass offset and sorting parameters to the database.
@@ -479,7 +479,7 @@ Thus, the method name results in a query expression of `SELECT … FROM person W
 <5> Find a single entity for the given criteria.
 It completes with `IncorrectResultSizeDataAccessException` on non-unique results.
 <6> In contrast to <3>, the first entity is always emitted even if the query yields more result documents.
-<7> The `findByLastname` method shows a query for all people with the given last name.
+<7> The `findByLastname` method shows a query for all people with the given `lastname`.
 <8> The `streamByLastname` method returns a `Stream`, which makes values possible as soon as they are returned from the database.
 ====