Handling of source documents

Line and column numbering (if enabled for a particular document) is now maintained for text nodes as well as element nodes. Previously the line and column reported for a text node were that of the parent element.

This enables more accurate location information to be provided for expressions in XSLT text value templates.

This change affects the line and column numbers reported by the saxon:line-number() and saxon:column-number() extension functions, as well as diagnostic output including the results of schema validation, the output of -T tracing, and so on.