Update to latest highlightjs version

[rwinch]

Asciidoctor is using an older version of highlightjs which can cause highlight errors. For example the following will render with the latest version of highlightjs (you can try using https://highlightjs.org/demo ):

@Configuration
@EnableNeo4jRepositories(basePackages = "com.acme.repositories",
    includeFilters = { @Filter(type = FilterType.REGEX, pattern = ".*SomeRepository") },
    excludeFilters = { @Filter(type = FilterType.REGEX, pattern = ".*SomeOtherRepository") })
class ApplicationConfiguration {

  @Bean
  EntityManagerFactory entityManagerFactory() {
    // …
  }
}

However, rendered with the Spring documentation it the number in the annotation name causes it to highlight incorrectly:

Unfortunately, asciidoctor is on an older version of highlight.js and updating is non-trivial due to breaking changes See asciidoctor/asciidoctor#3976

We should try and update to the latest version of highlightjs and ideally contribute it back to the community.