A follow-up to #368.

The current draft of the registry spec omits all human-readable descriptions. @aphillips noted in #368 (comment):

I assume this title (and others such as the one on line 24) are meant to be human readable descriptions of the function/input/parameter? If so, it's bad practice to make them an attribute--because they can't easily be localized that way. It's better to make subsidiary elements to contain natural language text. The title fields don't appear to be necessary to the functionality in any case.