Fix KeyType handling of "none"

[mgravell]

This totally isn't a duplicate of #3159 because I screwed up the branch and pushed this to main and had to --force-with-lease - that totally never happened, move along, nothing to see here.

fix #3156

second commit fixes the code-generator, which had some doc-inconsistent behaviour vs explicit "" which is meant to always mean "don't even look at this value"

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