`category` "MUST be an array of string values"

Hi there, don't know much about writing these specs but just noticed something that looks like an error to me, although I may just be misreading something.

The spec says "category MAY be present on any entry object which is a direct child of the top level feed object. If present, this property MUST be an array of string values."

But the examples show `category` as a single string: `"category": "Posts"`

Start by comparing the JF2 editor draft's definition of `category` with the examples cited in this issue. Resolve whether the specification or examples are inconsistent, then update the affected specification text or examples so they describe the same representation.

Written by the indexing model from the issue text.