Typo: it's --> its

Closes SF bug #637810.

Doc/lib/xmldom.tex

@@ -373,7 +373,7 @@ well.  This returns the clone.
 
 A \class{NodeList} represents a sequence of nodes.  These objects are
 used in two ways in the DOM Core recommendation:  the
-\class{Element} objects provides one as it's list of child nodes, and
+\class{Element} objects provides one as its list of child nodes, and
 the \method{getElementsByTagName()} and
 \method{getElementsByTagNameNS()} methods of \class{Node} return
 objects with this interface to represent query results.