Clarify Atom Binding 3.3.1's description of #propertyName values

An optional list of property names (propertyName values) which indicate to the server the properties whose values SHALL be included in the feed of Stored Query Entries made available at the results URL, to whatever extent those properties are present in each entry returned in the feed as a result of executing the query.

That should probably read "feed of Artifact Entries", not "feed of Stored Query Entries"