Retrieves the next page of query results.
The next() function retrieves the next page of query results.
The page size is defined by the limit()
function, can be retrieved using the pageSize property, and
navigating through pages is done with the prev() and
next() functions.
If items are added or removed between calls to next() the values returned
by WixDataQueryResult may change.
Note: The next() function is not supported for Single Item Collections.