label can now accept either a string, as before, or a more complex
object of {key: string; value: string} to allow defining labels for
both labels in keyvaluelist collection inputs.
key is only passed on to the server if collection is set to keyvaluelist
though it will accept both forms - key is dropped at submission-time.
labelcan now accept either astring, as before, or a more complex object of{key: string; value: string}to allow defining labels for both labels inkeyvaluelistcollection inputs.keyis only passed on to the server ifcollectionis set tokeyvaluelistthough it will accept both forms -keyis dropped at submission-time.