1.70.0
(feat): XML (TwiML) types can now carry XML comments. Comment(text) adds <!--text--> inside the element at its
position in the ordered content (interleaved with AddText segments and child elements), while
CommentBefore(text) / CommentAfter(text) render a comment immediately before or after the element
itself (as a sibling in its parent, or around the root element after the XML declaration). Comments in
parsed documents are preserved by FromXml and round-trip through ToXml; XmlElement.AddComment and
the new core.XmlComment node expose the same for untyped elements.