Creates an System.Xml.XmlProcessingInstruction with the specified name and data.
The new XmlProcessingInstruction.
Although this method creates the new object in the context of the document, it does not automatically add the new object to the document tree. To add the new object, you must explicitly call one of the node insert methods.
According to the W3C Extensible Markup Language (XML) 1.0 recommendation (www.w3.org/TR/1998/REC-xml-19980210), ProcessingInstruction nodes are only allowed within Document, Element, and EntityReference nodes, when the EntityReference node is not a child of an Attribute node.