Bump asciidoctorj from 2.5.8 to 2.5.9

Bumps [asciidoctorj](https://github.com/asciidoctor/asciidoctorj) from 2.5.8 to 2.5.9.
- [Release notes](https://github.com/asciidoctor/asciidoctorj/releases)
- [Changelog](https://github.com/asciidoctor/asciidoctorj/blob/main/CHANGELOG.adoc)
- [Commits](https://github.com/asciidoctor/asciidoctorj/commits)

---
updated-dependencies:
- dependency-name: org.asciidoctor:asciidoctorj
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

docs/pom.xml

@@ -73,7 +73,7 @@
                         <dependency>
                             <groupId>org.asciidoctor</groupId>
                             <artifactId>asciidoctorj</artifactId>
-                            <version>2.5.8</version>
+                            <version>2.5.9</version>
                         </dependency>
                     </dependencies>
                 </plugin>