Clarify which branch "older branch" refers to

[story645]

I made kind of a mess in #25034, partly cause i didn't quite grok which branch older branch is supposed to refer to here
https://github.com/MeeseeksBox/MeeseeksDev/blob/46fe439f28c406e90a7bb863b21ce3020eab3b20/meeseeksdev/meeseeksbox/commands.py#L895
and cherry picked into v3.7.x instead. I'd open the PR myself to fix this but I'm not totally confident which branch this should be, but I'd change this step to something like

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git checkout {older_branch}
git cherry-pick -x -m1 {merge_sha}