Add per-feature “unaffected” version in the hotfix mechanism #4324

Currently our hotfix system only lets us specify only one version at which ALL of the listed features are fixed. I never anticipated that we’d have to use hotfixes so often 😅

I suggest using a new format that is also easy to write: CSV. GitHub might also render a table for this

fit-textareas,21.5.1
avoid-accidental-submissions

Notice how the second line, doesn’t have a second value, so it’s not yet fixed. Also it doesn’t have to start with feature: since this new file needs to be parsed and not just used as-is