Several code refactors of the SaveLoad code #9338
Depends on #9335
Motivation / Problem
When you start fiddling with the SaveLoad code, you find many odd things. And sometimes they annoy me enough that you get this collection of commits.
First commit is #9335, after that:
I could have made 4 PRs out of this too, so if this is too hard to review, let me know, and I will split it up :)
Checklist for review
Some things are not automated, and forgotten often. This list is a reminder for the reviewers.
Also move it to static, as nobody else is using it.
…e generic Future additions will start using it for std::list too.
…part You can easily mistake SlList / SL_LST to be a list of SL_VAR, but it is a list of SL_REF. With this rename, it hopefully saves a few people from "wtf?" moments.