1-based source line number for a parsed node, or 0 if the parser did not
record one. @xmldom exposes lineNumber directly on Element/Attr nodes
(zero-based-internally, but exposed 1-based) when the document was parsed
from a string — matches Python's elem.sourceline.
Use this everywhere instead of poking (node as any).lineNumber so callers
cope cleanly with constructed-in-memory nodes (which have no source).
1-based source line number for a parsed node, or
0if the parser did not record one.@xmldomexposeslineNumberdirectly on Element/Attr nodes (zero-based-internally, but exposed 1-based) when the document was parsed from a string — matches Python'selem.sourceline.Use this everywhere instead of poking
(node as any).lineNumberso callers cope cleanly with constructed-in-memory nodes (which have no source).