`indexGenerator.py` doesn't seem to update `-stable` directories

### Jenkins and plugins versions report

n/a

### What Operating System are you using (both controller, and any agents involved in the problem)?

n/a

### Reproduction steps

1. Notice how https://get.jenkins.io/war/ and https://get.jenkins.io/war-stable/ look wildly different
2. Look at https://github.com/jenkinsci/packaging/blob/e8fa928d2fdc8058ecc8fdbdec5aae4cb2a9bead/bin/indexGenerator.py and various `publish.sh` scripts
3. Realize we're probably not generating `-stable` index pages

### Expected Results

1. Regular and `-stable` index pages to be largely in sync
2. Weekly Java requirements on the weekly page, LTS Java requirements on the `-stable` index page.

### Actual Results

* Information on LTS pages is outdated
* Weekly pages confusingly have both LTS and weekly Java requirements documented

### Anything else?

_No response_