Remove last vestiges of Java 17

[StackScribe]

Describe your use-case which is not covered by existing documentation.

A couple last instances of "java-17" that should be changed to "java-21":

• Search finds one instance of java-17 in Installing Jenkins on AWS/Downloading and Installing Jenkins
  • (Source in doc/tutorials/tutorial-for-installing-jenkins-on-AWS.adoc)
• git grep java-17 also finds four instances in doc/book/installing/linux.adoc. I don't know if those have any effect.

Reference any relevant documentation, other materials or issues/pull requests that can be used for inspiration.

No response

Are you interested in contributing a fix?

No response

[clintonsteiner]

I've reviewed the instances listed here and cannot find any remaining java-17 usages
Should be able to close

[Nimbusprogrammer]

I checked the latest jenkins.io repository and searched all the files referenced in this issue.

• content/doc/tutorials/tutorial-for-installing-jenkins-on-AWS.adoc
• content/doc/book/installing/linux.adoc

Both of these no longer contain any references to java-17. It looks like the documentation has already been updated as part of the Java 21 transition.

If there are any other files that still need updating, I can look into those as well.