[DFDL-WG] Use of xs:fixed and xs: prefix generally on XSD attributes

This may be a nit, but in prose when we want to distinguish an xsd attribute from a dfdl attribute or property, we prefix it with xs: as in xs:fixed, xs:nillable, etc. However, this is technically incorrect as those attributes are in no namespace. (XML Schema of XSD itself uses the default attributeFormDefault which is 'unqualified'.) A reader might think we are referring to some XSD construct they haven't heard of such as an <xs:nillable...> XSD element, but which doesn't exist. I am ok with keeping things as they are, or we can change to language like "XSD's nillable attribute" and "XSD's fixed attribute", and so forth. -- Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com