[XQuery] IBM-XQ-021: Automatic assignment of default namespace

(IBM-XQ-021) Section 3.7.4, Namespace Nodes on Constructed Elements: In 
the Note in this section, the second paragraph says that an implementation 
can choose to assign the default namespace (by generating a namespace 
declaration with a null prefix) when constructing an element. This is a 
dangerous thing to do. The string content of the element may contain some 
names that are intended to be in no namespace. Unexpectedly reassigning 
the default namespace would cause these names in element content to be 
interpreted incorrectly. I suggest deleting this paragraph.
--Don Chamberlin