5676 schemaComplete should be allowed only at 1 location

This seems to be an oversight. I do not anticipate any disagreement on this one. Please reply to indicate whether you agree with the proposal.

>From the bug:
=========
Currently the schemaComplte attribute is defined on the documentCollectionType
complex type. There are 2 elements defined to be of this type. Namely,
definitions & instances. Thus, it is possible to specify schemaComplete on the
definitions element (as described in the spec) as well as the instances element
(not described in the spec). The spec simply says that:

The schemaComplete attribute is defined on the definitions element and is used
to ...

It does not say whether one should ignore schemaComplete on other elements.
This seems to be an oversight.

Proposal:
1. Move schemaComplete from documentCollectionType to modelType.
2. Update spec text to reflect the above.