messagePropertyNames(field:prefixed:includeHasAndClear:)
Calculate the names to use for the Swift fields on the message.
func messagePropertyNames(field: FieldDescriptor, prefixed: String, includeHasAndClear: Bool) -> MessageFieldNames
If prefixed
is not empty, the name prefixed with that will also be included.
If includeHasAndClear
is False, the has:, clear: values in the result will be the empty string.