Address deprecated slice() method in ValuesBuilder

[wooldridge]

In #231 we addressed the slice() method in QueryBuilder but missed the ValuesBuilder counterpart. We need to update the param handling for that slice() method as well.

The zero-based slice version should be the default.

Also see: #360

[wooldridge]

ValuesBuilder as of 2.0.2 works with the array slice mode as the default as it uses the same method in mlutil as QueryBuilder to build the slice clause:

https://github.com/marklogic/node-client-api/blob/2.0.2/lib/values-builder.js#L332

The tests have already been updated for array slice mode in ValuesQuery slicing, see:

#360

What needs updating is the documentation for valuesBuilder.BuiltQuery#slice.

[wooldridge]

@kcoleman-marklogic, can you please review my updates to the documentation for valuesBuilder.BuiltQuery#slice, see the above PR?